The White House on Friday called the execution of U.S. journalist James Foley a "terrorist attack against our country" and sent strong signals that President Obama is considering military action against the Islamic State that could reach beyond Iraq.

Speaking to reporters in Martha's Vineyard, deputy national security adviser Benjamin Rhodes used some of the White House's strongest language to date in describing efforts to confront the Islamic State of Iraq and the Levant.

Asked if Foley's videotaped beheading by ISIS represented a terrorist attack, Rhodes was unequivocal. "Absolutely that represents a terrorist attack against our country and against an American citizen," he said.

Rhodes also concurred with a statement Thursday by the chairman of the joint chiefs of staff, Gen. Martin Dempsey, that the U.S. would have to go after ISIS in Syria, as well as Iraq, if it wanted to defeat the terrorist group. Rhodes noted that the U.S. was already providing assistance to moderate Syrian rebels, but he pointedly did not rule out military action there.

"We’ve made clear that if you come after Americans, we’re going to come after you, wherever you are," Rhodes said. 

Regarding the threat poses by ISIL, he added: "We're actively considering what is necessary to deal with that threat, and we’re not going to be restricted by borders."

The U.S. has been conducting military strikes against the Islamic State in Iraq since August 8, but in the days since Foley's murder, the rhetoric used against the group by senior U.S. officials has escalated significantly. President Obama earlier this week called ISIL "a cancer" and said the U.S. would be "relentless" against them.