New York - Russia on Tuesday vetoed a US-drafted resolution that would have granted a one-year extension to the mandate of a panel investigating who is behind chemical weapons attacks in Syria.
It was the ninth time Russia has used its veto power at the Security Council to block action targeting its Syrian ally.
Russia opposed renewing the mandate of the joint UN-Organisation for the Prohibition of Chemical Weapons (OPCW) panel before it releases a report on a sarin gas attack in Khan Sheikhun, which is expected on Thursday.
Continued use of chemicals
The United States, France and Britain have accused President Bashar al-Assad's forces of carrying out the April 4 attack on the opposition-held village, killing scores of people, including children.
After Russia cast its veto, US Ambassador Nikki Haley accused Moscow of "once again" siding "with the dictators and terrorists who use these weapons.
"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," Haley said in a statement.
"By rejecting the renewal of the work of the Joint Investigative Mechanism (JIM) - an independent, purely technical body - Russia has made it clear that it does not care about stopping the use of chemical weapons in the world".
A resolution requires nine votes to be adopted at the council, but five countries - Russia, Britain, China, France and the United States - can block adoption with their veto power.
China and Kazakhstan abstained, while Bolivia voted against the renewal and 11 other countries backed extending the mandate. Russia used its veto to block adoption.
More than 87 people died in Khan Sheikhun, drawing global outrage and prompting the United States to fire cruise missiles at a Syrian air base from which the West says the attack was launched.
UN war crimes investigators last month said they had evidence that the Syrian air force was behind the attack, despite repeated denials from Damascus.
Russia maintains that the sarin attack was most likely caused by a bomb set off directly on the ground, not by a Syrian air strike as alleged by the West.