Russia has vetoed a US-sponsored UN resolution that would extend the work of inspectors seeking to determine who was responsible for chemical weapons attacks in Syria.
Moscow accused Washington of calling the vote "to show up and dishonour Russia".
Russia's UN ambassador Vassily Nebenzia tried unsuccessfully to postpone the vote until next month, after the joint body comprising investigators from the UN and the chemical weapons watchdog issues a report on October 26.
The resolution was put to a vote on Tuesday and received 11 Yes votes, two No votes - from Russia and Bolivia - and two abstentions.
Mr Nebenzia said Russia has criticised the Joint Investigative Mechanism but does not want it terminated. It wants its mandate amended.
The resolution was sparked by the April 4 chemical attack in Khan Sheikhoun which killed more than 90 people.
US ambassador Nikki Haley, who is in Africa, pressed for a vote before the JIM report.
She said last week that Moscow wanted first to see if the report blames Syria for the Khan Sheikhoun attack, in which case it would have no faith in the JIM.
She called this position unacceptable.
"We can't work like that," she told reporters. "We can't go and pick and choose who we want to be at fault, who we don't."
Mr Nebenzia repeated and sharply criticised Haley's comments, telling the council: "We never, ever, ever put it in such a way.
"It's not us who pick and choose, it's you, the United States, you decided on the first day."
The US blamed the Syrian military for the attack in Khan Sheikhoun and launched a punitive strike days later on the Shayrat air base where it said the attack was launched.
Syrian President Bashar Assad has denied using chemical weapons
The attack in Khan Sheikhoun sparked outrage around the world as photos and video of the aftermath, including quivering children dying on camera, were widely broadcast.
A fact-finding mission by the chemical weapons watchdog, the Organisation for the Prohibition of Chemical Weapons, reported on June 30 that sarin nerve gas was used in the Khan Sheikhoun attack, but the mission was not authorised to determine responsibility. That job was given to the JIM.
Russia, a close ally of Syria, has repeatedly accused the US and its Western allies of rushing to judgment and blaming the Syrian government for sarin use in Khan Sheikhoun.
It has also criticized the June 30 report by the fact-finding mission as "very biased".
Ms Haley said in a statement after the vote: "Russia has once again demonstrated it will do whatever it takes to ensure the barbaric Assad regime never faces consequences for its continued use of chemicals as weapons.
"This is the ninth time Russia has protected Assad and his team of murderers by blocking the Security Council from acting.
"In doing so, Russia once again sides with the dictators and terrorists who use these weapons."