BBC's Paul Wood
Syrian Foreign Minister Walid Muallem has threatened to walk out of peace talks in Geneva just hours after they began, state media have said.
Mr Muallem told UN envoy Lakhdar Brahimi he would quit if "serious" discussions had not begun by Saturday.
The regime and the opposition have refused to meet face-to-face and are communicating through Mr Brahimi.
Later, Mr Brahimi said government and opposition delegates agreed to meet "in the same room" on Saturday.
Diplomats say they are now aiming at small concessions such as local truces rather than an overall peace deal.
The tranquil grounds of the United Nations, with elegant gardens sweeping down to Lake Geneva, have been transformed, and not in a good way. The atmosphere is tense, and often angry.
Representatives from both the Syrian government and the opposition have been striding back and forth, followed by packs of journalists, pushing, shoving, and shouting in an attempt to get the best shot, or the best sound-bite.
The long planned and much hoped for face-to-face meeting has not happened yet, and no-one is sure whether it will. The UN special envoy Lakhdar Brahimi is instead holding closed bilateral talks with the government, and then separately with the opposition.
The differences are the same as ever: the opposition wants a promise of a new transitional government, including the removal of President Assad, the government says their president stays exactly where he is - in power.
The violence has also driven 9.5 million people from their homes, creating a major humanitarian crisis within Syria and for its neighbours.
Fighting continued on Friday, with government forces bombing rebel-held areas in the northern city of Aleppo, according to the British-based Syrian Observatory for Human Rights.
Preliminary talks began on Wednesday in Montreux, with Mr Brahimi attempting to get both sides to agree to meet face-to-face.
Friday was supposed to be the first day of official talks, but neither side would meet the other.
Instead, Mr Brahimi met government delegates in the morning, and the opposition in the afternoon.
The Damascus delegation has said the main issue of the talks is finding a solution to foreign-backed "terrorism", by which it means the whole of the armed opposition.
Syrian state media quoted sources as describing the meeting between Mr Brahimi and Mr Muallem as productive in searching for common ground.
But the sources said Mr Muallem had told Mr Brahimi: "Should serious sessions fail to take place tomorrow [Saturday], the official Syrian delegation will leave Geneva."
The opposition, however, has insisted that the regime commit in writing to the 2012 Geneva I communique, which called for a transition process.
The communique urged Syria to form transitional governing authority that "could include members of the present government and the opposition and other groups".
The BBC's Bridget Kendall in Geneva says the talks are ostensibly about the implementation of the communique.
But she adds that 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.
Analysts say both sides have indicated a willingness to talk about local ceasefires, prisoner exchanges and establishing safe corridors for the delivery of aid.
One of the main sticking points between the government and the rebels is the role of Bashar al-Assad.
The opposition and most Western governments want him to step down from office as a condition for peace.
US Secretary of State John Kerry has called Mr Assad "a one-man super-magnet for terrorism".
But Syrian officials, backed by Russia, have flatly rejected any transition that insists on Mr Assad standing down.
Russia's Deputy Prime Minister Arkady Dvorkovich told the BBC that nobody other than Mr Assad could run Syria at the momenthttp://www.bbc.co.uk/news/world-middle-east-25880727