US claims it has proof about Syria chemical attack

Nauert said in a press briefing on Friday that the US has proof that the Syrian government was behind this attack, and will "continue to gather information and further assess it", Xinhua news agency reported.

"I can tell you this. Syria's responsible. We are all in agreement," she said. "We can say that the Syrian government was behind this attack."

However, she refused to show the evidence, saying the thing was "sensitive."

She also refuted the accusation of Russia in the UN meeting earlier on Friday that Britain was behind the Syria attack, saying Moscow tried to "completely change the story" and "turn it upside down."

"The UK, I'm confident in saying, had absolutely nothing to do with it," she added. "It is the assessment of the US government, the British government, the French government."

Meanwhile, Russia's Defence Ministry Spokesman Lgor Konashenkov said that "we have evidence that proves Britain was directly involved in organising this provocation" in Douma.

Activists and rebels in Syria claimed that Syrian forces used chlorine gas in the attack on April 7 against Douma in the rebel-held area near Damascus.

The Syrian government has denied the allegations and called the reports fake news that the West uses to justify attacking the country.