U.N. peace envoy Staffan de Mistura met on Monday with Syrian opposition members to discuss his plan to "freeze" fighting in the country's war-ravaged second city Aleppo, his spokeswoman said.
"The talks started today at 11:00 am (0900 GMT) and lasted for eight hours with representatives from the main armed and non-armed groups," Juliette Touma told Agence France-Presse.
"We met with them separately in Gaziantep," in southern Turkey, she said, adding that the U.N. delegation was four-strong, including de Mistura.
The U.N. envoy first unveiled his plan for a ceasefire in Aleppo in October, touting it as a way for desperately-needed aid to reach the ruined former economic hub.
Syria's government has said it would "study" the proposal.
On Monday, al-Watan newspaper, which is close to the regime of Syrian President Bashar Assad, said the government wanted the ceasefire to be limited to Aleppo city, while rebels want it to extend to the Bab al-Hawa border crossing with Turkey.