* Russia says will present plan on Syrian chemical arms in nearest future
* Syria agrees to cede control of chemical arms in hope of averting U.S. strike
* West wants more proof that the initiative is serious (Adds Syria accepting proposal, Putin and Obama discussed plan)
By Gabriela Baczynska and Alexei Anishchuk
MOSCOW, Sept 10 (Reuters) - Russia said on Tuesday it was working with Syria on an "effective, clear, concrete" plan to put Syria's chemical weapons under international control with the aim of averting a U.S. strike.
Syrian state television quoted Syrian Prime Minister Wael al-Halki as saying President Bashar al-Assad's government backed the initiative, confirming what his foreign minister had earlier told the speaker of the Russian parliament.
Faced with scepticism in the West about whether Russia and Syria are serious about the surprise initiative, Russian Foreign Minister Sergei Lavrov said the plan would be presented soon and that Moscow would welcome input from the U.N. chief and other Security Council powers.
The Kremlin, meanwhile, said Russian President Vladimir Putin and U.S. President Barack Obama had discussed the idea of putting Syria's chemical arsenal under control when they met on the sidelines of a G20 summit on Friday.
Lavrov told a news conference: "We, the Russian side, are at the present time working on preparing an effective, clear, concrete plan, for which purpose contacts with the Syrian side are being conducted literally at this minute ...
"We hope to present this plan in the very near future, and will be prepared to finalise it and work it out with the involvement of the U.N. Secretary General, the Organisation for the Prohibition of Chemical Weapons (OPCW) and members of the Security Council."
Syrian Foreign Minister Walid al-Moualem told the speaker of the Russian parliament that Damascus accepted the proposal, Interfax news agency reported.
"We held a very fruitful round of talks with Foreign Minister Sergei Lavrov yesterday, and he proposed an initiative relating to chemical weapons. And in the evening we agreed to he Russian initiative," Moualem said.
He added Syria had agreed because this would "remove grounds for American aggression".
Obama said the deal "could potentially be a significant breakthrough" but also expressed scepticism amid Western concern that the proposal might just a bid to buy time.
Obama, struggling to persuade a reluctant and divided Congress to back potential U.S. intervention, said a handover of Syria's chemical weapons stockpile to international authorities would "absolutely" put any U.S. military strike on hold.
Lavrov announced Russia's proposal at a hastily arranged news conference late on Monday, hours after U.S. Secretary of State John Kerry said Syria could avoid a U.S. strike by surrendering all its chemical weapons within a week.
Although Kerry's comments indicated he was not making a serious offer, Obama said he had discussed the scenario with Putin while he was in Russia for the G20.
"(It) is not an entirely Russian initiative. It stems from contacts we have had with our American colleagues, from yesterday's statement by John Kerry, who said strikes could be avoided if this problem is solved," Lavrov said after talks with Libyan Foreign Minister Mohammed Abdel Aziz. (Writing by Steve Gutterman and Gabriela Baczynska; Editing by Timothy Heritage and Kevin Liffey)