The divided Syrian opposition meets Friday to decide whether to join landmark talks next week aimed at ending almost three years of brutal conflict, facing intense pressure from Western allies to attend.

On the eve of the National Coalition's meeting in Istanbul, US Secretary of State John Kerry made a powerful plea to the exiled group to decide in favor of attending the long-delayed talks opening in Switzerland on January 22.

And at key preparatory talks with Russia in Moscow on Friday, the Syrian regime said it was ready to swap prisoners with the rebels in the first such mass exchange since the conflict began in March 2011.

The announcement by Foreign Minister Walid Muallem could mark another diplomatic success for Russia after the Kremlin managed to convince Damascus last year to renounce its chemical weapons to avert US air strikes.

Next week's so-called Geneva II conference is aimed at finding a way to install a transitional government to help chart an end to the civil war, which has claimed 130,000 lives and sent millions fleeing.

Muallem said Syria would "make every effort to ensure this event is a success and meets the aspirations of the Syrian people and the direct orders of President Bashar al-Assad."

But parts of the deeply fractured Syrian opposition are wary of being drawn into a process they fear could result in Assad clinging to power and had set his departure as a condition for joining the peace talks.

"The United States ... urges a positive vote," Kerry told reporters. "The Syrian people need to be able to determine the future of their country, their voice must be heard."

But Friday's opposition meeting in Istanbul - which comes more than a week after the coalition failed to agree a united stance - are expected to be fraught.

"The debate will be long and difficult because the coalition leadership is caught between a rock and a hard place," said one Western diplomat.

A key bloc, the Syrian National Council, has already threatened to pull out of the coalition if it votes in favor of attending Geneva II.

Complicating the situation are the continuing fierce battles between mainstream rebels in Syria and Al Qaeda linked jihadists that monitors say have killed over 1,000 people in two weeks.

British media reported earlier this week that the US and Britain had even threatened to cut support to the opposition if it failed to send a delegation to Switzerland.

AFP