WASHINGTON : Hundreds of additional US forces including trainers, advisers and commandos are needed in the fight against the Islamic State, Pentagon officials have concluded, prompting them to urge the White House to approve further deployments to Iraq and Syria in the coming weeks.

Defence Department officials told the White House that the US-led effort to destroy the Islamic State requires still more manpower in addition to the roughly 3,700 American troops already in Iraq, The New York Times reported on Friday. Citing senior White House and Pentagon sources, The Times said the officials determined hundreds more military experts are needed in the region to take on the terror group, with one suggesting that the number of troops increases to 4,500.

Admission from the Obama administration that more troops are needed followed recent remarks from Defence Department officials who expressed a desire to adjust US operations abroad.

“We’re looking for opportunities to do more,” Defence Secretary Ashton Carter told CNN in an interview last week. “We’re not looking to substitute for local forces in terms of governing the place and policing the place.”

“I have personally reached out to the ministers of defence in over 40 countries around the world to ask them to contribute to enhancing the fight against ISIL - more special operations forces, more strike and reconnaissance aircraft, weapons and munitions, training assistance, as well as combat support and combat service support,” Carter said recently, using an alternative acronym for the group also known as ISIS. “I expect the number of trainers to increase, and also the variety of the training they’re giving.”

Indeed, Defence Department officials told The Times that the Pentagon is not prepared to add ground troops to its anti-ISIS fight - a point President Obama has stuck with throughout the year-and-a-half fight. Instead, rather, hundreds of additional experts from the US and allied militaries would be sent overseas to assist training Iraqi, Kurdish and Syrian opposition fighters in the region.

Already, though, the Pentagon’s attempt at preparing foreign rebels to fight the terror group has raised a number of red flags, and a $500 million programme intended to train and equip Syrian opposition fighters was nixed in October after officials conceded that the number of rebels who had been successfully vetted failed to surpass single digits.

In the past, the Times said, the Pentagon’s requests for additional troops in both Iraq and Afghanistan have been met with scepticism by President Obama, and his aides have said he has resented what he has regarded as efforts to pressure him. But the rise of the Islamic State has alarmed the White House, and a senior administration official said Thursday that the president is willing to consider raising the stakes in both Iraq and Syria.

The United States already has about 3,700 troops in Iraq, counting a small handful of Special Operations forces on the ground in Syria. One official said that he did not anticipate that number increasing to more than 4,500 over time, and even that increase, the official said, could come incrementally, much as the deployment of the 3,700 American troops occurred over the period of a year and a half. During that time, the White House and the Pentagon have taken pains to avoid describing the deployments as combat troops, instead calling them special operators, trainers and advisers.