Russia has vetoed a UN Security Council resolution that would have extended an international inquiry into chemical weapons attacks in Syria.

It is the 10th time Moscow has used its veto powers at the UN in support of its ally since the conflict began.

US ambassador to the UN, Nikki Haley, accused Russia of undermining the organisation's ability to deter future chemical attacks.

The Russian ambassador dismissed the criticism.

The Joint Investigative Mechanism (JIM) was set up in 2015 to identify perpetrators of chemical attacks. It is the only official mission investigating the use of chemical weapons in Syria.