The United States said Tuesday the newly formed opposition National Coalition is "a legitimate representative" of the Syrian people, but stopped short of recognizing it as a government-in-exile.

"We now have a structure in place that can prepare for a political transition, but... we're looking for it to still establish the types of technical committees that will allow us to make sure our assistance gets to the right places," State Department deputy spokesman Mark Toner said.

"We do think this is a legitimate representative of the Syrian people, that it does reflect the Syrian people... that diverse group of Syrian people," he told journalists.

"We look forward, obviously, to supporting the national coalition as it charts a course for the end of Assad's bloody rule, and marks the start, we believe, of a peaceful, just and democratic future for the people of Syria."

The diverse forces involved in the Syrian coalition agreed on Sunday to unify their fighting forces under a supreme military council and set up a national judicial commission for rebel-held areas in Syria.

The move which came after talks in Doha came after Washington pushed the Syrian National Council to broaden its membership, saying it was not representative of all the groups fighting to topple President Bashar al-Assad.

France on Tuesday became the first country to recognize the newly formed opposition group as the sole representative of the Syrian people and said it was time to review whether the rebels should be given arms.

But Toner said the US policy of providing only non-lethal support and humanitarian aid to the Syrian rebels remained unchanged.

Britain has also said it wants to see more evidence that the grouping has strong support inside Syria before formally recognizing it as effectively a government-in-exile.