Russia has vetoed for the second time in 24 hours to block a UN Security Council resolution to re-authorise an investigation into the use of chemical weapons in Syria, media reports said on Saturday.
Friday night's development was the third veto of an extension for the chemical weapons investigators in the past month, reports CNN.
After Russia vetoed a compromise 30-day extension of the mission proposed by Japan, US Ambassador Nikki Haley said that Russia "saw fit to waste our time".
UK Ambassador Matthew Rycroft said he was, "frankly astounded" that Russia would block a resolution to restructure how the mission operates to meet some of Moscow's concerns.
Swedish Ambassador Olof Skoog called for immediate additional private consultations.
The Security Council was holding those consultations Friday night, but no further vote was expected.
The mandate for the Joint Investigative Mechanism (JIM) to inspect for chemical weapons ran out at midnight on Friday.
Russia vetoed the resolution along with Bolivia. China was the sole country to abstain.
Italian UN Ambassador Sebastiano Cardi, President of the Security Council, said the group "will continue to work in the coming hours and days to find a common position in light, of course, of this crucial non-proliferation issue that we have been debating for the last days".
On April 4, more than 80 people were killed in a sarin attack on the rebel-held town of Khan Sheikhun -- an attack that prompted the US to launch 59 Tomahawk cruise missiles at a Syrian airbase, CNN reported.
A joint report from the UN and international chemical weapons inspectors last month determined the Syrian regime of President Bashar al-Assad was responsible for the attack.
Syria has repeatedly denied it had anything to do with the attack and rejects that it has any chemical weapons.
This is the 11th time that Russia, which supports Assad, has used its veto to stop a resolution on Syria, where some 500,000 people have died in a civil war that erupted in March 2011, reports Efe news.
The JIM was created in 2015 with the support of all five permanent members of the Security Council.
A Russian draft resolution to maintain the JIM with the changes sought by Moscow was defeated handily on Thursday, receiving only four votes.
Syria had handed over its chemical weapons arsenal to the Organisation for the Prohibition of Chemical Weapons under a 2013 accord brokered by Washington and Moscow.