British Prime Minister David Cameron said on Wednesday that there was “a growing body of limited but persuasive information” showing that the Syrian government had used and was continuing to use chemical weapons such as sarin gas.

“The room for doubt about this continues to diminish,” Cameron told parliament. “There’s an urgent need to start a proper negotiation to force a political transition and to bring this conflict to an end.”

Cameron said he would fly to Russia on Friday to discuss the matter with President Vladimir Putin. “In Syria the atrocities continue to mount,” he said.

But he cautioned against rushing to judgment. “On chemical weapons it is important we learn the lessons on how information has been presented in the past,” he said.

(Reuters)