(Reuters) -- Syria's new opposition leaders are struggling to win over powerful Islamist rebel combat units, whose radical elements question whether the "hotel warriors" of the fledgling coalition can offer their fighters any real support.
Islamists have established themselves as the most effective, best armed and fastest growing units in the 20-month-old uprising against President Bashar al-Assad.
Many of them are wary of the National Coalition for Syrian Opposition and Revolutionary Forces, set up earlier this month in an attempt to unify Assad's fractured opponents and win greater international support.
"They are the hotel warriors, we are the men in the trenches. No one should be allowed to marginalize us, politically or militarily. These coalitions are just fighting over us and not for us," said Yassir al-Karaz, a leader in the rebel Tawheed Brigade in northern Aleppo province.
Most rebels are conservative but politically moderate and willing to work with diverse opposition groups. But they were left to their own devices for months in an uprising they dubbed an "orphan revolution" and the challenge to bring them into the fold is made bigger by the rising role of radicals, including al Qaeda-style fighters in Syria.
The problem for the new coalition is maintaining the backing of this crucial bloc of Syrian fighters on the ground while bolstering support from Western powers wary of funding a movement that may be linked to extremist groups.
While the coalition has won formal recognition from Turkey, France, Britain and Gulf Arab states, the response from many Islamist fighters has been skeptical or downright dismissive.
"We are with the coalition - for now. We want to see what it is going to do for us," said a fighter from one of the biggest Islamist brigades in the capital Damascus.
"It is known that we want weapons, we want a no-fly zone. Can it do that? We will see. We are not going to wait forever. With or without them, we are fighting and we are going to win."
The Islamists have grown increasingly influential through the course of a civil war in which 38,000 people have been killed, but won minimal aid from Western powers. Radical groups such as the secretive Jabhat al-Nusra and independent foreign fighters have also gained a foothold.
Among the opposition, many civilians and fighters view the Islamists in an increasingly positive light. Their brigades are effective on the battleground and in the villages of northern Syria many credit them with maintaining electricity and water.
Unlike the many opposition groups that formed both in Syria and abroad, such as the ill-fated Syrian National Council that the National Coalition has eclipsed, Islamist units have clear chains of command and discipline. That increasingly appeals to Syrians now living in chaos and violence.
FLEXING THEIR POWER
Islamist fighters say it is only fair they assert their power after months of being ignored in political squabbling abroad while they fought Assad's forces on the ground.
Some put their frustration on display earlier this week when they announced the creation of an Islamic state in a video rejecting the National Coalition.
The immediate backlash from most rebel leaders and Syrian activists pushed many fighters in the video to retract their remarks the next day. But it laid bare the deep mistrust which the coalition has to overcome.
"Our video caused a big racket internationally, which is what we needed," said one fighter present at the Islamic state meeting, who asked not to be named.
"We need to know we are going to get help and support from the coalition because Jabhat al-Nusra don't want us to have anything to do with them. And right now, al-Nusra is our main support. So they need to show us they can do something for us."
Some fighters told Reuters that Jabhat al-Nusra organized the video in response to attempts by the new coalition to drive a wedge between al-Nusra and less radical Islamist groups.
That could be difficult because few of the hardline groups fight independently, choosing instead to spread their men out among rebel units and giving them widespread influence.
TWO MORE MONTHS
The coalition has asked for patience from fighters, but seems aware it has a limited window. Walid al-Bunni, a leader and spokesman for the coalition, said that while rebels would not be given representation in its political wing, they would all have a voice in the soon-to-be formed military council.
"All groups will get a role, and equal aid and support. They will need to talk extensively to create consensus, but no group will be discriminated against," he told Reuters.
"We face a difficult task because we must prove ourselves to both the fighters and foreign powers who have different demands. I think we will need a month or two to meet some of the fighters' basic needs."
Some fighters are demanding results faster than that. Islamist groups in the central city of Homs say they are not only asking for weapons, they want to see the coalition do something about Assad's month-long siege on the city, which has choked off most supplies to the rebels.
"We have given him two weeks to lift the siege on Homs. This is how we know that he is doing business and they are serious," said the leader of an Islamist battalion in the city, who spoke on Skype and requested anonymity.
Those demands alone appear well beyond the power of the coalition to deliver, and satisfying the Sunni Muslim Islamists will be even more difficult given the Western pressure on the coalition to give a voice to minorities, many of whom support the Alawite president because they fear Sunni supremacy.
In a bid to show inclusiveness, the new coalition appointed an Alawite opposition leader as ambassador to France - a move which many fighters said showed the coalition is beholden to the West and not Syrians on the ground.
"Qatar and France are the ones who worked to form it, and the Americans," said an Islamist fighter in Homs. "Is this why we are fighting, so that we are followers of these countries?"
For fighters like him, there is no more time for patience. "We have our eyes on them and watching them closely - we will not tolerate any mistakes or any hesitations."
By Erika Solomon and Mariam Karouny
Editing by Giles Elgood.