By Phil Stewart

BRUSSELS, Feb 12 (Reuters) - U.S. Defense Secretary Ash Carter said on Friday he expected both Saudi Arabia and the United Arab Emirates to send special operations forces to Syria to help local opposition fighters in their drive to retake the city of Raqqa from Islamic State.

Carter, who has long sought greater participation of Sunni Arab allies in Syria, did not disclose how many commandos he expected them to deploy nor the timing of those deployments.

But he suggested they would play a major role taking back Raqqa, the Islamic State's defacto capital, from the militants.

"We're going to try to give opportunities and power to ... particularly Sunni Arabs in Syria who want to re-seize their territory back from ISIL, especially Raqqa," Carter told reporters travelling with him in Brussels.

Carter made the remarks after talks with his UAE and Saudi counterparts on Friday and Thursday respectively.

Four months of Russian air strikes in Syria have helped Syrian President Bashar al-Assad claw back territory from rebels fighting government forces, alarming Gulf Arab states who back the insurgents.

Saudi Arabia had concentrated its military efforts over the last year on the conflict in Yemen, where it is leading a coalition of mainly Gulf Arab forces battling Houthi fighters who control the capital, Sanaa.

But it appears to be widening its focus. Carter said on Thursday Saudi Arabia committed to expand its role in the air campaign and the United Arab Emirates said it would restart its participation.

Saudi Arabia and Gulf states took part on Thursday in the largest gathering so far of defence ministers from the U.S.-led coalition against Islamic State, which Carter hosted at NATO headquarters in Brussels.

Carter said the group collectively approved a campaign plan that aims to recapture the two main Islamic State strongholds of Raqqa in Syria and Mosul in Iraq, as well as grappling with the group's spread beyond its self-declared caliphate.

That plan, however, does not include deployment of large-scale foreign ground forces to Iraq and Syria and Carter stressed that coalition commandos were meant to bolster local forces, not replace them.

"We're not looking to substitute for them, any more than we're looking to substitute for the Iraqi forces. But we are looking to enable them strongly and help them organise themselves," he said.

The United States has already deployed a small group of special operations forces to Syria and Carter said other allies, beyond Saudi Arabia and the United Arab Emirates, were considering commando deployments.

"Some don't even like to acknowledge the operations of special forces, but there are a number of them. And we are the organiser of them," Carter said.

Asked wheher the Saudis and UAE were already operating in Syria, Carter said: "No. They've had kind of liaisons there ... We're talking about amping that up."

(Editing by Louise Ireland) ((phillip.stewart@thomsonreuters.com; +1-202-898-8398; Reuters)(Messaging: phillip.stewart.thomsonreuters.com@reuters.net))

Keywords: MIDEAST CRISIS/CARTER SAUDI