The Syrian government delegation has threatened to quit peace talks in Geneva if "serious" discussions do not begin by Saturday.
Foreign Minister Walid Muallem issued the threat on Syrian state media after his team held talks with UN negotiator Lakhdar Brahimi. Mr Brahimi is due to meet the Syrian opposition separately later on Friday.
This is the third day of the Geneva conference, but the first in which negotiations get under way in earnest. There were initial hopes of a joint meeting between the two sides, but later it emerged that Mr Brahimi would hold talks with each separately. Both sides blame the other for this setback.
The Damascus delegation complained about recent remarks made by the opposition chief, Ahmed Jarba, who said President Bashar al-Assad and his regime were a "political corpse" that could not be part of Syria's future.
For its part, the opposition said it would not meet government delegates face-to-face until they signed a written commitment accepting the Geneva communique drafted 18 months ago, which calls for a transitional government.
The talks are ostensibly about the implementation of the communique, but the views of the government and the opposition are so diametrically opposed that Friday's discussions may get no further than preliminary attempts to set a common agenda.
