President Barack Obama yesterday urged quick congressional action authorising the use of military force against Syria and won the support of leaders from both parties in the House of Representatives for limited strikes against President Bashar al-Assad’s forces.

Obama told congressional leaders at a White House meeting that the United States has a broad plan to help the rebels defeat Syrian government forces.

After the meeting, the top two Republicans in the House – Speaker John Boehner and Majority Leader Eric Cantor – and top Democrat Nancy Pelosi said they would back military action against Syria.

“Only the United States has the capability and the capacity to stop Assad and to warn others around the world that this type of behaviour is not going to be tolerated,” Boehner told reporters. “I believe that my colleagues should support this call for action.”

The support came as Obama ramped up his lobbying effort for military action in response to what Washington says was a sarin gas attack by the Syrian government that killed more than 1,400 people, hundreds of them children, near Damascus on August 21.

“What we are envisioning is something limited. It is something proportional. It will degrade Assad’s capabilities,” Obama told reporters.

Obama said on Saturday he will seek lawmakers’ approval for a possible military strike, slowing what had appeared to be plans for a swift action. He has faced stiff resistance from some lawmakers and strong public opposition to US action.

The House and the Senate return from their summer recess on September 9. Both chambers would have to approve the authorisation, and it remains unclear whether the Obama administration has the votes.