Western powers have lashed out at Russia after it vetoed a United Nations resolution that would have condemned the suspected use of chemical weapons in northern Syria and demanded a speedy investigation.

The vote on the Security Council resolution drafted by Britain, France and the United States was 10 in favour, Russia and Bolivia against, and China, Kazakhstan and Ethiopia abstaining.

After the vote on Wednesday, Britain's UN Ambassador Matthew Rycroft looked at the Russian envoy and asked: "How could anyone look at the faces of lifeless children and choose to veto a resolution condemning those deaths?"

He said samples taken from the site of the April 4 attack had been analysed by British scientists and tested positive for the nerve gas sarin. He said President Bashar al-Assad's government was responsible.

US Ambassador to the UN Nikki Haley told the council that "with its veto, Russia said no to accountability, Russia said no to cooperating with the UN investigation, Russia said no to helping keep peace in Syria. Russia chose to side with Assad, even as rest of the world, even the Arab world, comes together to condemn the murderous regime."

It was the eighth veto by Russia, a close ally of Assad, on a Western-backed Syria resolution and reflected the deep division that has left the UN's most powerful body struggling to tackle the use of banned chemical weapons and to help end the six-year Syrian conflict.

China has vetoed six resolutions.

Call for investigation

The draft resolution would have required Assad's government to provide access for investigators and information such as flight plans.

Russia's UN deputy ambassador Vladimir Safronkov told the council before the vote that a resolution was unnecessary, and the draft put forward by the Western powers pre-judged that the Syrian government was responsible for the attack on Khan Sheikhoun in which nearly 90 people died.

Safronkov said Russia's foreign minister asked US Secretary of State Rex Tillerson during talks earlier on Wednesday in Moscow to jointly request the Organisation for the Prohibition of Chemical Weapons "to immediately put together an independent international mission" to visit Khan Sheikhoun and the airbase that the US attacked in retaliation.

Tillerson is considering the request, he said, "and we expect that Washington will have a constructive reaction".

READ MORE: Syria chemical attack survivors vow to fight for justice

In Washington, President Donald Trump was asked if he thought it was possible that Syrian forces could have launched the alleged attack, from an airbase they share with Russian forces, without Russia knowing about it.

"I think it's certainly possible. I think it's probably unlikely," he said. "I would like to think that they didn't know, but certainly they could have. They were there."

After the vote at the UN, French President Francois Hollande said Russia "bears a heavy responsibility" for continuing to protect Assad and blocking a united international response.

US-based Human Rights Watch said the veto "tells those responsible for chemical attacks that they can flout the laws of war and attack civilians without consequences".

Under a 2013 deal between the US and Russia, struck after a chemical attack in suburbs of Damascus killed hundreds of people, Syria was supposed to dismantle its chemical weapons arsenal.

"The Russians really became the guarantor for Assad's behaviour in regards to chemical weapons and the guarantor for Assad's promise that he had given them all up," Jessica Ashooh, of the Atlantic Council, a foreign policy think-tank in Washington, DC, told Al Jazeera.

She said that in light of that deal, the Idlib attack was "very embarrassing" for the Russians.

"We saw a veto from Russia today because the reality is, there's absolutely no question that Bashar al-Assad and his regime were responsible for the strikes."