Russia has vetoed a UN Security Council resolution that would have extended for one year the work of international inspectors investigating chemical-weapons attacks in Syria.
The October 24 veto came immediately after Moscow failed to secure a one-month postponement of the vote in order to allow the body to consider a report from the inspectors that is due on October 26.
Russian UN Ambassador Vasily Nebenzya said the United States -- which drafted the resolution -- called the vote "to show up and dishonor Russia."
The October 26 report will cover an April 4 chemical-weapons attack using sarin gas in the village of Khan Sheikhun, which was controlled by the Syrian opposition at the time.
The United States, France, and Britain have accused forces loyal to Assad of carrying out the attack, which left more than 80 people dead.
Russia, which is a key ally of Syrian President Bashar al-Assad, has criticized the inspectors, or Joint Investigative Mechanism (JIM), in the past.
On October 13, Russian diplomat Mikhail Ulyanov accused the JIM of failing to carry out a "qualitative investigation" of the incident.
The JIM has previously determined that Syrian government forces were responsible for three chlorine-gas attacks in 2014 and 2015 and that Islamic State (IS) militants had used mustard gas.
The Syrian government has denied ever using chemical weapons.
After the Russian veto, U.S. Ambassador to the United Nations Nikki Haley issued a statement accusing Moscow of "once again" siding with dictators and terrorists.
"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's statement said.
"We are disappointed, we are very disappointed that Russia put what it considered to be political considerations over the Syrian people who were so brutally murdered," State Department spokeswoman Heather Nauert told a regular briefing on October 24.
In addition to Russia, Bolivia voted against the resolution, while China and Kazakhstan abstained. The other 11 Security Council members voted in favor.
It was the ninth time Russia has used it UN veto power to support Assad.
The JIM was authorized by the Security Council in 2015 and had its mandate renewed for another year in 2016.
Its current mandate expires on November 17.