A ceasefire between the warring sides in a Syrian town and two villages has been extended until Sunday, sources on both sides said on Friday.
The ceasefire between rebels on one hand and the Syrian army and its Lebanese ally Hezbollah on the other began on Wednesday. It halted fighting in the town of Zabadani near the Lebanese border and the villages of Kefraya and al-Foua in the northwest.
Sources involved in the negotiations say they are focused on agreeing a withdrawal of rebel fighters from Zabadani and the evacuation of civilians from the two Shi'ite villages in the northwest.
"There is no final agreement yet but talks continue," a source on the insurgents' side said.
An official close to the Syrian government said negotiations were going slowly.
Zabadani has been the focus of a weeks-long campaign by the Syrian army and the Lebanese guerrilla group Hezbollah aimed at driving out insurgents who are still holed up inside.
The rebels have meanwhile targeted the two Shi'ite villages in a parallel offensive.
The negotiations have been led on the insurgents' side by the Sunni Islamist rebel group Ahrar al-Sham.
Iran, which backs Hezbollah and Syrian President Bashar al-Assad, helped to bring about the ceasefire, as did Turkey, which has supported insurgents fighting against Damascus.
The ceasefire began at 6 a.m. (0300 GMT) on Wednesday and was initially agreed to last two days.
Issues being discussed included safe passage for wounded fighters who want to leave Zabadani, and the later withdrawal of all fighters, the official close to the Syrian government said.
The rebels had submitted a list of names of wounded fighters they want to evacuate initially, the official said.
(By Mariam Karouny; Writing by Tom Perry; Editing by Gareth Jones and Digby Lidstone)