Cameron: Syria using chemical weapons

British prime minister David Cameron said that evidence was accumulating of the Syrian government’s past and continued use of chemical weapons such as sarin gas.

“There is a growing body of limited but persuasive information showing that the regime has used and continues to use chemical weapons including sarin and the room for doubt about this continues to diminish,” Cameron told parliament.

Cameron said he had spoken to US secretary of state John Kerry about Syria, saying he had welcomed a joint Russia-US push for new peace talks.

“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 said he would fly to Russia tomorrow 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 of how information has been presented in the past.”

Meanwhile, the Obama administration is providing $100m in new Syria aid, US officials said, but the money is for humanitarian purposes only and not linked to any decision on arming Syrian rebels.

The new funds will help support 1.4m Syrian refugees, including many in US ally Jordan, and hundreds of thousands of other civilians still trapped by the violence inside Syria’s border. Total US humanitarian assistance in the two-year war will climb to $510m.

The Obama administration has said it is considering providing weapons to vetted units in the armed opposition, among other military options, following last week’s revelation of a US intelligence assessment suggested chemical weapons use by the Assad regime. The US also is looking for ways to halt the violence that has killed more than 70,000 people.

But the US maintains deep reservations about providing direct military assistance, given the growing presence of al Qaeda-linked and other extremists in the rebel ranks.

Underscoring the administration’s goal of a peaceful transition of power to end the war, Kerry met for more than five hours with Russian president Vladimir Putin and foreign minister Sergey Lavrov in Moscow.

Afterward, Kerry and Lavrov declared that the US and Russia would convene an international conference on Syria in the coming weeks with the goal of corralling Assad’s government and opposition representatives into peace talks.

Kerry said the US would make its decision on arming the rebels in part on the progress of that effort.