Malala 'heartbroken' by massacre
Education campaigner and Nobel peace prize winner Malala Yousafzai has led condemnation of the "atrocious and cowardly" attack on a school in Pakistan which claimed the lives of at least 130 people and left scores injured.
The teenager joined a stream of Western politicians and campaigners in criticising the Pakistani Taliban, who claimed responsibility for opening fire on the Army Public School in the city of Peshawar.
Prime Minister David Cameron warned that the battle with Islamist terrorism "is going to be the struggle of our generation" .
Speaking to the House of Commons Liaison Committee, Mr Cameron paid tribute to those who died in Peshawar, adding: "The scale of what has happened in Pakistan simply defies belief. It is a dark, dark day for humanity when something on this scale happens with no justification.
"There is not a belief system in the world that can justify such an act.
"I think what this shows is the worldwide threat that is posed by this poisonous ideology of extremist Islamist terrorism. It is nothing to do with one of the world's great religions - Islam, which is a religion of peace.This is a perversion.
"But we have to recognise the scale of what we face in this country, but also - as we see - around the world. And we must with our allies use everything we have in our power to defeat it."
Seventeen-year-old Malala, who was shot in the head by the Taliban in 2012 after speaking out for girls' rights to education, said: " I am heartbroken by this senseless and cold-blooded act of terror in Peshawar that is unfolding before us.
"Innocent children in their school have no place in horror such as this.
"I condemn these atrocious and cowardly acts and stand united with the government and armed forces of Pakistan whose efforts so far to address this horrific event are commendable.
"I, along with millions of others around the world, mourn these children, my brothers and sisters - but we will never be defeated."
The attack has taken the lives of at least 135 people, the vast majority of whom are children, a state official said. At least another 114 people were injured in the attack, deemed a "revenge" strike after Taliban members were killed by the Pakistan military.
US president Barack Obama condemned the attack as "horrific", saying: "By targeting students and teachers in this heinous attack, terrorists have once again shown their depravity.
"We stand with the people of Pakistan, and reiterate the commitment of the United States to support the government of Pakistan in its efforts to combat terrorism and extremism and to promote peace and stability in the region."
A Pakistani military source told US TV network NBC that at least 10 attackers wearing police uniforms and suicide vests stormed the army-run school. The gunmen were reported to have fired at random inside the school before the building was surrounded by Pakistani troops, who exchanged fire with the militants.
The source said: "They burnt a teacher in front of the students in a classroom. They literally set the teacher on fire with gasoline and made the kids watch."
Most of the school's 500 children are understood to have been evacuated, but many were being held hostage in the building.
Gunfire and explosions were heard shortly after the militants entered the school at around 10am local time (5am UK time). A number of teachers and a member of the security forces are believed to be among those killed.
The school is sited on the edge of a military cantonment in Peshawar, and some of the pupils are thought to be the children of members of the armed forces.
Taliban spokesman Mohammed Khurasani said six suicide bombers had carried out the attack in revenge for the killing of Taliban members by Pakistani forces.
"We targeted the school because the army targets our families. We want them to feel our pain," said a Taliban spokesman.
Hundreds of Taliban fighters are thought to have died in a recent military offensive in Waziristan and the Khyber region.
Nigel Inkster, a British former MI6 assistant chief, said the incident could be the first of several "revenge" hits by Taliban fighters.
He said: "It is an attack of revenge, and there is possibly more where this came from."
Pakistani prime minister Nawaz Sharif, who described the attack as a "national tragedy", told reporters in Peshawar: "I feel that until and unless this country is cleansed from terrorism, this war and effort will not stop, no one should be doubtful of this.
"Such attacks are expected in the wake of a war and the country should not lose its strength."
News images of the aftermath of the attack showed boys in blood-soaked school uniforms with green blazers being carried from the scene.
Police officer Javed Khan said army commandos quickly arrived at the school and exchanged fire with the gunmen.
Pakistani television showed soldiers surrounding the area and pushing people back.
One of the wounded students, Abdullah Jamal, was shot in the leg during a first-aid class.
"I saw children falling down who were crying and screaming," he said. "I also fell down. I learned later that I have got a bullet. All the children had bullet wounds. All the children were bleeding."
Peshawar is a city of more than three million people situated in the north west of Pakistan, close to the Khyber Pass crossing into Afghanistan.
Over the decades since the Soviet occupation of Afghanistan in the 1980s, it has housed many thousands of refugees seeking to escape unrest in its troubled neighbour, and it has been used as a base by Afghan fighters.
Khyber Pakhtunkhwa, the province of which Peshawar is the capital, has been a focus of the struggle between the authorities and the Pakistani Taliban, and the city has been the scene of a string of militant murders, abductions and bombings, most notably a 2009 car bomb which killed 137 people.
Syed Ibne Abbas, Pakistan High Commissioner for the UK, told BBC News: "This is what makes news. I am not in any way defending this as a small incident - it is very tragic, ask the parents who have lost loved ones. But this is one incident where they have been looking to get publicity.
"We will go after these terrorists, whatever it takes. I think we need to improve our intelligence and our tactics. This was a soft target attack."