ISTANBUL - The Syrian National Coalition (SNC), the main opposition group based in Istanbul, said on Monday that it agreed to join the Geneva II conference on condition that President Bashar al-Assad play no role in a transitional governing body.

"The coalition's participation should be on the basis that Bashar al-Assad, his assistants and remnants have no role in the transitional period and the future of Syria," the SNC's spokesperson Louay Safi said at a press conference in Istanbul.

The coalition also demanded the release of detainees, and the immediate opening of humanitarian corridors for the entries of the Red Cross, the Red Crescent and other humanitarian agencies to enter into the besieged areas.

The United States and Russia are exerting efforts to convene the Geneva II peace talks by the end of this year with an aim to end the 31-month crisis in Syria.

The planned conference is a follow-up to last year's international meeting in Geneva that drafted a peace roadmap for Syria but was never materialized.

Earlier on Saturday, SNC spokesman Khalid Saleh said that the United Nations is the only body to organize the Geneva conference and set the agenda. "We are waiting an invitation from UN Secretary-General Ban Ki-moon."