UNITED NATIONS - Russia on Tuesday vetoed a US-drafted Security Council resolution on an investigative mechanism for chemical weapons use in Syria.

Twelve of the 15 members of the Security Council voted in favor of the US text, while Russia and Bolivia voted against it. The draft failed to be adopted as Russia has veto power. China abstained.

Before the vote, US Ambassador to the United Nations Nikki Haley said her delegation had tried hard to incorporate Russian proposals into the draft so long as they would not compromise the impartiality of investigation.

She said the US text was "the bare minimum" that the Security Council can do to respond to reports of the latest chemical attack in Douma, Syria, on Saturday.

Russia has also tabled a draft resolution for vote on Tuesday -- also on an investigative mechanism for chemical weapons use in Syria.

Haley said the main difference between the US-drafted text and the Russian one is that Russia wanted to choose the investigators and assess the outcome while the US text allows for truly independent investigation.

"Our resolutions are similar, but there are important differences. The key point is our resolution guarantees that any investigations will truly be independent. Russia's resolution gives Russia itself the chance to choose the investigators and then to assess the outcome. There is nothing independent about that," she told the Security Council.

"The United States is not asking to choose the investigators, and neither should Russia. The United States is not asking to review the findings of any investigation before they are final, and neither should Russia," she said.

Russian Ambassador to the United Nations Vassily Nebenzia, who spoke after Haley, argued that the US draft prejudges the outcome of an investigation.