The US is considering the use of military force in Syria, the country's top general has said.
He told a Senate hearing that under current conditions, he believed Syrian dictator President Bashar Assad would still be in power in a year's time. "Currently the tide seems to have shifted in his favour," he said.
The Obama administration has said that it will supply small arms to Syrian rebels, but has so far resisted calls from some leading Senators to intervene with US military forces or implement a no-fly zone.
Gen Dempsey said that Mr Obama had asked him whether the US "could", but not whether it "should", stage a military intervention. The "issue is under deliberation inside of our agencies of government," the general said.
Gen Dempsey has previously expressed scepticism about deploying US force.
"The decision on whether to use force is the decision of our elected officials," he said.
His deputy, Admiral James Winnefeld, said: "There are a whole range of options that are out there. We are ready to act if we're called on to act."
Gen Dempsey said that options presented to Mr Obama include "kinetic strikes" – military language for actions involving lethal force.
The Pentagon constantly updates military options for the White House. But Gen Dempsey's comments were the clearest yet that it is deliberating a direct intervention into the bloody conflict.
Those options would include missile strikes on key regime infrastructure, including chemical weapons sites, imposing no-fly zones or a ground invasion. Another course of action would be drone attacks against rebels linked to al-Qaeda if the administration decided to strike on both sides of the conflict.
But a president who has ended the war in Iraq and is winding down the US military role in Afghanistan has made clear to aides that he does not want to involve American forces in another military quagmire.
There is particular concern that radical Islamists are gaining ground among the opposition.
Gen Dempsey's comments come the day after his British counterpart told The Daily Telegraph that Britain must be prepared to "go to war" if it wishes to restrain the Syrian regime by implementing no-fly zones and arming the rebels.
"If you want to have the material impact on the Syrian regime's calculations that some people seek" then "ground targets" would have to be "hit", said General Sir David Richards, the outgoing head of armed forces.