DAMASCUS - Prospects for a Syria peace conference in Geneva next month looked dim Wednesday after key opposition leaders spurned efforts by Western and Arab powers to persuade them to attend.

A meeting in London on Tuesday between the opposition leaders and 11 governments from the Friends of Syria group produced little more than a joint statement that President Bashar al-Assad should play no future role in government.

Leaders of the National Coalition - the main opposition umbrella group - insisted they would not take part in a conference in late November unless regime change and Assad’s departure were on the table.

A defiant Assad has shown no sign of backing down after a two-and-a-half-year civil war that has left more than 115,000 people dead, saying he is ready to stand for re-election when his current term ends in 2014.

Assad has systematically refused to recognise the Coalition as a legitimate negotiating partner and rejected its demands for him to step down.

British Foreign Secretary William Hague said the London meeting had urged the Coalition to “commit itself fully” to the so-called Geneva 2 talks.

He said the Friends of Syria agreed that they would put their “united and collective weight” behind efforts to form a transitional government and that “Assad would play no role in that future government of Syria.”

US Secretary of State John Kerry took a similar position, saying Assad had “lost all legitimacy.”

But he too urged the opposition to go to Geneva, saying Syria was at risk of “implosion” if the war continued and that the only alternative to a negotiated settlement was “continued, if not increased, killing.”

Meanwhile, Syria is expected to hand over a detailed plan for the destruction of its chemical arsenal in the next 24 hours, days ahead of deadline, the world’s watchdog said Wednesday.

The detailed plan is the next step for Damascus under the terms of a US-Russian deal to head off military strikes on Syria agreed last month which calls for all its chemicals to be destroyed by mid-2014.

“We expect Syria’s initial declaration of its chemical weapons programme within the next 24 hours,” spokesman Michael Luhan told reporters in The Hague, where the OPCW is based.

President Bashar al-Assad’s regime has already handed over an inventory of its chemicals, weapons and facilities, and international inspectors are already busy inspecting and destroying them.

Syria has until October 27 (Sunday) to submit its “initial” plan of how to destroy its weapons, in accordance with Article III of the Chemical Weapons Convention.

A joint OPCW-United Nations mission has now checked 18 of 23 declared sites in Syria, destroying production equipment at almost all of them, Luhan said.

Meanwhile, Syrian authorities have released 14 women detainees as part of a weekend hostage exchange but more than 100 others are still being held, a prominent human rights activist said Wednesday.

Nine Lebanese Shiite hostages held for 17 months by a rebel group in northern Syria were exchanged on Saturday for two Turkish pilots detained in Lebanon since August.

The release of scores of female detainees held in regime jails formed part of the deal brokered by Turkey, Qatar and Lebanon.

“Fourteen of the women whose names were on the list” were freed late Tuesday, activist Sema Nassar told AFP. “For their own safety, they will have to leave the country.”

The women were on a list of 128 names of female detainees handed to the Syrian authorities as part of the exchange deal, she added.