Ashton Carter
Ashton CarterReuters

The United States believes Turkey should become more active in the air war against Islamic State (ISIS), U.S. Defense Secretary Ashton Carter said on Tuesday, according to Reuters.

"We need it to do more within its own territory, so it controls its border, which it has not done effectively since ISIL first arose," Carter told a hearing in Congress, using an acronym for the Islamic State.

"We would like them to operate more both in the air and on the ground. Most of the air operations are not directed at ISIL. They are directed at the PKK," he added, referring to the Kurdistan Workers' Party (PKK) group.

Turkey in recent days has been embroiled in controversy after it downed a Russian fighter jet.

Carter was echoing comments made earlier Tuesday by President Barack Obama, who called for Turkey and Russia to end their dispute over the downing of the Russian fighter jet and focus instead on ISIS.

"I want to be very clear: Turkey is a NATO ally. The U.S. supports Turkish rights to defend itself and its airspace and its territory," Obama said after meeting his Turkish counterpart Recep Tayyip Erdogan in Paris.

"We all have a common enemy and that is ISIL and I want to make sure we focus on that threat," Obama added.

Carter also said earlier Tuesday that the United States is deploying "specialized" troops in Iraq to fight the ISIS, including by leading raids against the jihadists over the border in Syria.

Speaking to the House Armed Services Committee, the Pentagon chief said that a "specialized expeditionary targeting force" was being deployed in Iraq to help Iraqi and Kurdish Peshmerga forces battle ISIS.  

"American special operators bring a unique suite of capabilities that make them force multipliers," Carter said. "Where we find further opportunity to leverage such capability, we are prepared to expand it."

He said the special forces would also be able to intervene in neighboring Syria, where Washington has already announced it is sending about 50 special operations troops.

U.S. special forces have been directly involved in at least one such operation already. In October, dramatic footage emerged of an operation deep inside ISIS territory to free dozens of prisoners slated for execution. The daring operation involved both American and Kurdish special forces, and at least one U.S. serviceman was wounded in the course of the mission.