Washington: The Obama administration is debating a more robust intervention in Syria, including possible US airstrikes, in a significant escalation of its weeks-long military assault on the Islamic extremist group that has destabilised neighbouring Iraq and killed a US journalist, officials said on Friday.

While President Barack Obama has long resisted being drawn into Syria’s bloody civil war, officials said recent advances by Islamic state of Iraq and the Levant (Isil) militants have made clear that it represents a threat to the interests of the United States and its allies. The beheading of James Foley, the American journalist, has contributed to what officials called a “new context” for a challenge that has long divided the president’s team.

Officials said the options include speeding up and intensifying limited US efforts to train and arm moderate Syrian rebel forces that have been fighting Isil as well as fighting the government of President Bashar Al Assad. Another option would be to bolster other partners on the ground to take on Isil, including the Syrian Kurds.

But US officials said they would also take a look at airstrikes by fighter jets and bombers as well as potentially sending special operations forces into Syria, like those who failed to rescue Foley and other hostages on a mission in July. One possibility officials have discussed for Iraq that could be translated to Syria would be a series of unmanned drone strikes targeting Isil leaders, much like those conducted in Yemen, Somalia and Pakistan.

Whether Obama would actually authorise a new strategy remained unclear, and aides said he has not yet been presented with recommendations.

The president has long expressed scepticism that more assertive action by the United States, including arming Syrian rebels as urged in 2011 by Hillary Rodham Clinton, then the secretary of state, would change the course of the civil war there. But he sent out a spokesman on Friday to publicly hint at the possibility a day after the chairman of the Joint Chiefs of Staff said Isil could not be defeated without going after it in Syria.

“If you come after Americans, we’re going to come after you, wherever you are,” Benjamin J. Rhodes, the president’s deputy national security adviser, told reporters in Martha’s Vineyard, where Obama is on a much-interrupted vacation. “We’re actively considering what’s going to be necessary to deal with that threat and we’re not going to be restricted by borders.”

US operations against Isil militants in Syria would expand the scope and goals of the military intervention Obama ordered in Iraq two weeks ago. At the time, the president said he authorised airstrikes to defend US personnel and prevent the genocide of religious minorities threatened by Isil.

But he has also ordered strikes to help Iraq’s government reclaim control of the vital Mosul Dam from Isil. Sending US warplanes or drones to cross the border into Syria would mean that he was now taking on the mission of degrading or even crippling Isil, which has established what it calls an Islamic caliphate on a wide band of territory across the two countries.

“Common sense suggests you need to hit them in Syria,” said Steven Simon, a former White House adviser to Obama on the Middle East. “Everyone understands well enough that you can’t defeat an insurgency that has a cross-border safe haven, so you have to do something.”

Critics of the original Iraq intervention said escalating into Syria would represent exactly the kind of mission creep they warned against.

“We’ve seen this movie before and we know how it ends,” said Stephen Miles, advocacy director of Win Without War, a national coalition formed to oppose the 2003 invasion of Iraq ordered by President George W. Bush. “Unfortunately, we see at the end of the day it’s almost always the case that the extremists are emboldened. We play into their hands by giving them what they want, which is a battle with the West.”

An expanded intervention into Syria would represent a striking turnaround for a president who has opposed such a move before, and some administration officials therefore doubt that he will agree. From the start of the Syrian civil war, Obama’s response has been marked by a pattern of heightened public statements and indications of stepped-up involvement, followed by far less action than suggested.