* Russia urges Syrian opposition coalition to use dialogue
* Says new coalition should reject outside interference
* United opposition useful if it talks to Damascus-Gatilov
By Steve Gutterman
MOSCOW, Nov 12 (Reuters) - Russia said on Monday a new Syrian opposition coalition that aims to oust President Bashar al-Assad, should seek an end to the Syrian crisis through negotiation and reject outside interference.
The Russian Foreign Ministry gave the coalition, formed in Qatar on Sunday with Western and Arab backing, a cool reception in a statement which cited media as saying its members had agreed not to enter talks with Assad's government.
Russia's "main criterion ... remains the readiness of such alliances to act on the platform of a peaceful resolution of the conflict by Syrians themselves, without external interference, through dialogue and negotiations," the ministry said.
Deputy Foreign Minister Gennady Gatilov said separately, on Twitter: "Unification of the Syrian opposition can be helpful if it enters into political dialogue with the government."
Representatives of groups including rebel fighters, veteran dissidents and minority groups agreed - after days of wrangling and cajoling by Arab, U.S. and other officials - to join a new assembly that can form a government-in-exile.
The United States had promoted the plan to unite factions into a more inclusive body than the widely criticised Syrian National Council (SNC). France said it would seek international recognition of the new entity "as the representative of the aspirations of the Syrian people".
An SNC member based in Moscow said the group had decided to join the coalition in hopes that what he called promises of extensive aid, including weapons, would be borne out.
"There was concern that various states promised a lot - Western, Arab states - that they would ... generously help with material, humanitarian aid and even provide weapons, serious weapons," Mahmoud al-Hamza told a news conference on Monday.
"We have no guarantee that there will be that kind of help, but there are strong affirmations, and so the Syrian National Council entered into the coalition, so that there are no grounds to say we oppose the unification of the opposition."
Russia says Syria's crisis must be resolved without foreign meddling or military action. In the statement, Foreign Ministry spokesman Alexander Lukashevich said some Syrian opposition groups had declined to join the new entity.
He said Moscow would continue to maintain contact with the Syrian government and "the whole spectrum of opposition forces", encouraging them to take a constructive approach.
The West has criticised Russia and China for vetoing three U.N. Security Council resolutions aimed at putting pressure on Assad to end a conflict activists say has killed more than 38,000 people since protests first erupted in March 2011.
Russia denies trying to prop up Assad, whose nation has been an avid buyer of its weapons and hosts a naval supply facility that is Moscow's only military base outside the ex-Soviet Union.