The United States plans to deploy "specialized" troops in Iraq to fight the self-declared "Islamic State" (IS) group, US Defense Secretary Ashton Carter said Tuesday.

The Pentagon chief, who was addressing the House Armed Services Committee, said that a "specialized expeditionary targeting force" was being deployed in Iraq to aid Iraqi and Kurdish peshmerga forces in fighting IS. There are about 3,500 U.S. troops in Iraq.

Carter said the move was in "full coordination with the Government of Iraq," but he did not specify the number of personnel that the US plans to send. Nor did Carter say where the troops would be based. "The raids in Iraq will be done at the invitation of the Iraqi government and focused on defending its borders and building the Iraqi security force's own capacity," Carter said.

Unilateral operations in Syria

"This force will also be in a position to conduct unilateral operations into Syria," Carter added. President Barack Obama had previously announced he was sending fewer than 50 special operations forces to Syria.

IS fighters took control of vast swathes of territory in the trouble-torn countries of Iraq and Syria in 2014.

Carter also said he was "prepared to expand" the role of its special operations forces in Syria, and called on other nations to ramp up efforts to defeat IS.

"The international community - including our allies and partners - has to step up before another attack like Paris," he said.

"The more contributions we receive from other nations, the greater combat power we can achieve using our own force," Carter added.

"That's for starters," Carter told the hearing. "If we find more forces that we can enable in this way we're prepared to do more ... I have every reason to believe the president will allow us to do more and authorize us to do more when we have more opportunities."

ap/jm (AFP/AP,Reuters)