Nine Britons, 23 US citizens and 80 children are reported to be among those killed when a passenger jet crashed over the eastern Ukraine border amid claim and counter-claim that it was shot down by a missile.
Pictures and video from the scene showed bodies strewn around the site of the crash amid the charred wreckage of Malaysian Airlines flight MH17, which fell to Earth near the town of Grabovo, about 50km from the Russia-Ukraine border, while 283 passengers and 15 crew members were on board.
The passengers on the flight included 154 Dutch, 27 Australians, 38 Malaysians - including 15 crew, 11 people from Indonesia, four Germans, four Belgians, three from the Philippines and one Canadian, BBC News reported an airport official as having said.
Meanwhile, the Ukrainian Interior Ministry said 23 US citizens were travelling on the aircraft. The nationalities of the remaining passengers were still being confirmed. 80 children were also on board, according to various agencies reporting from the scene.
The Malaysian national carrier said that the six British passport holders were travelling from Amsterdam to Kuala Lumpur on board the Boeing 777-200.
A spokesman from The Foreign and Commonwealth Office said it was working to identify any British victims of the tragedy. “We are aware of the reports and are urgently working to establish what has happened," he said.
Malaysia's Prime Minister Najib Razak said on Friday that the Malaysia Airlines jetliner did not make any distress call, adding that its flight route had been declared safe by the global civil aviation body. He added investigators "will leave no stone unturned".
While the cause of the crash has not been determined, US Vice President Joe Biden cautiously suggested the crash was "not an accident" and that the jet had "apparently blown out of the sky", while a US official said that, while its origin was unclear, a surface-to-air missile was probably responsible.
"I say 'apparently' because we don't actually have all the details. I want to be sure of what I say. Apparently, shot down. Shot down, not an accident. Blown out of the sky," he said.
The aircraft departed from Amsterdam at 12.14am local time, 15 minutes later than scheduled, according to flight records.
It should have arrived in Malaysia at 6:10am local time, but did not enter Russian airspace when it was expected to, a Russian aviation source told Reuters.
The Eurocontrol organsiation, which co-ordinates European air traffic control, closed air routes in eastern Ukraine on Thursday evening.
The incident came one day after US President Barack Obama levied broad economic sanctions on Russia as punishment for its threatening behaviour towards Ukraine.
Amid tensions in the region, Russian President Vladmir Putin blamed Ukraine for the crash, the Kremlin said in a statement early on Friday.
Putin opened a meeting with his economic advisers by calling for a moment of silence over the crash, but added: "This tragedy would not have happened if there were peace on this land, if the military actions had not been renewed in southeast Ukraine. And, certainly, the state over whose territory this occurred bears responsibility for this awful tragedy."
Russian-backed Ukrainian rebels and the Ukraine government have accused each other of carrying out the ground-to-air strike, with both issuing firm denials of any involvement in the disaster.
Video purports to show crash
Ukrainian President Petro Poroshenko responding by calling the crash a "terrorist" attack which posed a challenge to the whole world, his website said.
"Today's tragedy showed again that terrorism is not localised, but a world problem. And the external aggression against Ukraine is not just our problem, but a threat to European and global security," he said.
Shortly after the crash, rebel leader Alexander Borodai told the RIA-Novosti agency that discussions were under way with Ukrainian authorities on calling a three-day cease fire for humanitarian reasons.
He added that international organisations would be allowed into the region.
Prior to the suggestion of a truce, the Poroshenko rejected claims by Ukraine rebels that Kiev was responsible and said his country's armed forces did not shoot at any airborne targets.
“We do not exclude that this plane was shot down, and we stress that the Armed Forces of Ukraine did not take action against any airborne targets,” he said.
“We are sure that those who are guilty in this tragedy will be held responsible," he added.
An official statement from the Ukraine government blamed Russian air defence systems it claimed are protecting "terrorists" in the area, according to the Daily Telegraph.
It said: "A large passenger aircraft Boeing 777, performing a flight between Amsterdam and Kuala Lumpur, was shot down in the eastern part of Ukraine. According to the General Staff of Ukrainian Armed Forces, the plane was shot down by the Russian Buk missile system as the liner was flying at an altitude of 10,000 meters.
"Ukraine has no long-range air defence missile systems in this area.
"The plane was shot down, because the Russian air defence systems was affording protection to Russian mercenaries and terrorists in this area.
"Ukraine will present the evidence of Russian military involvement into the Boeing crash.
Anton Gerashenko, an aide to the Ukrainian Interior Minister, wrote on his Facebook page that the Boeing airliner, which was flying from Amsterdam to Kuala Lumpur, was at an altitude of 33,000ft when it was hit by a missile fired from a Buk launcher and crashed near the city of Donetsk - a stronghold of pro-Russian rebels.
But Russia’s military said that none of its military planes had been flying close to the Russia-Ukraine border on Thursday, RIA Novosti reported citing a military official.
Earlier, Aleksandr Boroday, Prime Minister of the recently established Donetsk People's Republic, denied the jet had been shot down by the rebels and called the incident a “provocation by the Ukrainian military”.
“We confirm that the plane crashed not far from Donetsk,” Boroday said. “Representatives of Donetsk People's Republic have headed to the scene.”
“Self-defence forces have no air-defence, which could target transport aircraft at that height,” he told Interfax.
In separate reports by Interfax, an unidentified pro-Russian separatists said they had found the jet's black box flight recorder.
The Ukrainian Prime Minister Arseniy Yatsenyuk has ordered an investigation into what he has called an "airplane catastrophe", his spokeswoman Olga Lappo said on Thursday.
Elsewhere, world leaders issued statements expressing their shock, and calling for potential culprits to be brought to justice.
President Obama called the crash a "terrible tragedy", and said his government's priority was to determine whether any Americans were killed.
During a pre-planned phone conversation, Obama and Putin discussed the crash, the White House and Kremlin both confirmed.
Meanwhile, US senator John McCain warned that there will be “hell to pay” if the Russia military or Ukrainian separatists are deemed to have had any involvement in the 'incident'.
“If the Malaysian plane was shot down, this is obviously a game changer and has horrific consequences," he warned.
“It has the earmarks of a tragic mistake made by someone who had the capability to just shoot down an aircraft, and we know at least from the last couple of weeks that that could be Russian or separatist Russian capability.”
"But if it is the result of either separatist or Russian actions mistakenly believing this was a Ukrainian war plane, I think there’s going to be hell to pay and there should be," he said in an interview on MSNBC, citing previous reports of separatists shooting down Ukrainian fighter planes.
His comments followed a tweet by the Malaysian Prime Minister, following his later statement, in which he said he was "shocked" by reports of a plane crash, and that an investigation was being launched into the incident immediately.
As pictures emerged showing loved ones of those on board the flight gathering at both Kuala Lumpur International Airport, Sepang, and Schiphol airport in Amsterdam, Netherlands Prime Minister Marke Rutte also said he was "deeply shocked" by the crash, NL Times reported.
"I am deeply shocked by the tragic news about the crash of Malaysia Airlines flight MH17 from Amsterdam to Kuala Lumpur via Ukrainian territory,” he said.
“Very much is still unclear about the facts, the circumstances and the passengers.”
Late on Thursday, newly appointed Foreign Secretary Philip Hammond called for an UN-led international investigation to establish what caused the flight to crash, with a meeting of the Government's emergency committee - Cobra - expected to meet on Friday.
"I'm deeply shocked by this appalling incident and I send my heartfelt condolences to all those who may have lost family and friends. We're determined to get to the bottom of understanding what has happened here," he said.
Australian Prime Minister Tony Abbott said in a statement that if the plane crash was deliberate, it constituted an "unspeakable crime" for which the perpetrators must be swiftly brought to justice.
"It is a very, very sad time, made worse by reports that it might be a crime rather than an accident," Abbott said.
Shortly after the crash, Malaysia Airlines posted a tweet on its official account confirming it had "lost contact of MH17 from Amsterdam".
"The last known position was over Ukrainian airspace. More details to follow."
It said early on Friday that all of its European flights will take routes avoiding Ukraine.
Virgin Airlines, Lufthansa and British Airways have confirmed that they are diverting most of their flights away from Ukrainian airspace.
A spokesman from BA said: “The safety and security of our customers is always our top priority. Our flights are not using Ukrainian airspace, with the exception of our once a day service between Heathrow and Kiev.
4 October 2001 - Siberia Airlines Flight 1812 crashes over the Black Sea en route from Tel Aviv, Israel to Novosibirsk, Russia. Ukraine later admits that the disaster was probably caused by an errant missile fired by its armed forces. Evhen Marchuk, the chairman of Ukraine's security council, conceded that the plane was probably been brought down by "an accidental hit from an S-200 rocket fired during exercises".
29 May - Rebels in eastern Ukraine shoot down a government military helicopter amid heavy fighting around Slovyansk, killing at least 12 soldiers including a general, officials say. Acting Ukrainian president Oleksandr Turchynov tells parliament in Kiev that rebels used a portable air defence missile to bring down the helicopter. He says 14 died, including General Serhiy Kulchytskiy.
24 June - Ukrainian government says a military helicopter has been shot down over a rebel-controlled area in Slovyansk.
14 July - A Ukrainian military transport plane is shot down along the eastern border with Russia but all eight people aboard managed to bail out safely, the defence ministry says. Separatist rebels claim responsibility for downing the Antonov-26, but Ukrainian officials swiftly rule that out and blamed Russia instead.
16 July - A Ukrainian air force fighter jet is shot down by a missile fired from a Russian plane, according to Ukraine's Security Council. The pilot of the Sukhoi-25 jet is forced to bail out after his plane was hit, says spokesman Andrei Lysenko. Meanwhile, pro-Russian rebels claim responsibility for strikes on two Sukhoi-25 jets.
17 July - Almost 300 people die after a Malaysia Airlines plane is apparently shot down over Ukraine.
Disaster strikes again for Malaysia Airlines
Almost incredibly, Malaysia Airlines finds itself at the centre of a world aviation disaster for the second time this year.
It is only a few months since the Far East carrier was embroiled in what has become one of the great plane mysteries - the disappearance of flight MH370.
Now another Malaysia Airlines Boeing 777 lies wrecked in the Ukraine - seemingly the victim of a missile attack.
It was on March 8 that flight 370, carrying 239 passengers and crew veered far off course for unknown reasons during a flight from Kuala Lumpur to Beijing.
Initially, it was thought that the plane would soon be located. But weeks, and finally months, have passed - with the search areas changed and different theories being expanded - and still there has been no sign of the aircraft.
The search continues as does the heartache for the families of those lost on the flight.
Now today, comes news that of all the carriers to be involved in what appears to be an act of sabotage it should be beleaguered Malaysian Airlines.
Once more their managers have had to tell the world that they have lost contact with one of their aircraft. Now there are some who doubt whether the airline can recover from this.
BUK missile designed to take down aircraft
The BUK missile system is a set of medium range surface-to-air missile systems which were first developed in the Soviet Union and continue to be produced by Russia. A Buk division of Ukraine's armed forces was reportedly relocated to Donetsk region on Wednesday.
Designed to take out cruise missiles, aircrafts, helicopters and short range ballistic missiles, they can reach altitudes of up to 25km (15.5 miles or 82,000ft), according to the manufacturer's website.
Developed by Moscow firm Almaz-Antey, they are thought to have been used during the Russian war with Georgia in the territory of South Ossetia in 2008.
The manufacturer's website, which also lists military equipment including radar and naval missile systems, displays two models of Buk launchers - the Buk-M1-2 and the Buk-M2E.
A description of the Buk-M1-2, which has an altitude target range of up to 25km (15.5 miles or 82,000ft), reads: "The "Buk-M1-2" ADMC is designed to provide air defence for troops and facilities against attacks from current and future high-speed manoeuvring tactical and strategic aircraft, attack helicopters including hovering helicopters, and tactical ballistic, cruise, and air-to-air missiles, in conditions of heavy radio jamming and counter fire; as well as to destroy water and ground surface targets."
Meanwhile, the Buk-M2E "is designed to destroy tactical and strategic aircraft, helicopters, cruise missiles, and other aerodynamic aircraft at any point in their range of operation, along with tactical ballistic and aircraft missiles, and smart air bombs in conditions of heavy enemy counter fire and radio jamming; as well as to attack water and ground surface contrast targets."