WASHINGTON - Defence Secretary Ashton Carter on Tuesday said the United States will ramp up attacks on Islamic State jihadists in Syria and Iraq, with additional air strikes and even direct action on the ground.

Testifying before the Senate Armed Services Committee, Carter said he expects more actions like the one last week that freed dozens of captives but left an American commando dead in Iraq.

“We won’t hold back from supporting capable partners in opportunistic attacks against ISIL, or conducting such missions directly, whether by strikes from the air or direct action on the ground,” Carter said.

He did not elaborate on what he meant by “direct action on the ground,” and the Obama administration opposes committing US ground forces to Syria.

Carter said the United States would focus its efforts on the IS stronghold of Raqqa in northern Syria and boost support for rebel groups fighting the jihadists.

“We expect to intensify our air campaign, including with additional US and coalition aircraft, to target ISIL with a higher and heavier rate of strikes,” Carter said, using an alternate name for IS.

“This will include more strikes against ISIL high-value targets as our intelligence improves,” he added. Carter’s pledge to intensify strikes comes as the US-led coalition has in fact been striking fewer targets in Syria in recent months.

Pentagon officials insist the diminished tempo reflects a lack of decent targets, and has nothing to do with Russia launching its own bombing campaign a month ago.

France will host a meeting on the Syria crisis with Western and Arab allies later on Tuesday, Foreign Minister Laurent Fabius said. The “working dinner” at the French foreign ministry will include “the main partners engaged with France in dealing with the Syrian crisis: Saudi Arabia, United Arab Emirates, Jordan, Qatar, Turkey, Germany, the United States, Italy and Britain,” Fabius said in a statement.

“They will discuss the means to bring about a political transition towards a united and democratic Syria, respectful of all communities, while also reinforcing our fight against terrorism,” he added.

Tuesday’s meeting will feature mainly lower-rung officials, with the United States sending its deputy secretary of state Tony Blinken in the place of his boss, John Kerry.

Britain said it was “unlikely” that Foreign Secretary Phillip Hammond would take part.

France was not included in four-way talks on Syria between Russia, the United States, Saudi Arabia and Turkey which took place on Friday.

A Russian spokesman said those four countries were working on organising another possible meeting this Friday in Vienna.

Fabius said last week that France is working towards presenting a draft UN Security Council resolution to stop President Bashar al-Assad’s regime from using barrel bombs.

It remains highly unlikely that Russia, Syria’s ally, would allow such a measure, which comes amid Western criticism of Moscow’s dramatic intervention in the war to support Assad.