There is no evidence that militant opposition groups in Syria have used chemical weapons.

There is no evidence that militant opposition groups in Syria have used chemical weapons, a spokesperson for British Prime Minster David Cameron said.

Cameron said Wednesday that there was “limited but persuasive” intelligence that Syrian army used the nerve agent sarin against insurgents, and that he would be traveling to Russia on Friday for urgent talks on the matter with President Vladimir Putin.

Cameron was referring to talks in the Black Sea resort of Sochi, which are part of a US-Russian plan to try to force a political transition in Syria.