The Syrian government will leave UN peace talks if no "serious work sessions" are held by Saturday, state television quoted foreign minister Walid al-Moualem as saying.
Mr Moualem reportedly told international mediator Lakhdar Brahimi, "If no serious work sessions are held [by Saturday], the official Syrian delegation will leave Geneva due to the other side's lack of seriousness or preparedness".
Mr Brahimi met a Syrian government delegation today, a meeting described as having a "positive atmosphere."
The mediator is due to meet the Syrian opposition delegation later today.
Syria's regime and opposition have agreed that women and children can leave the besieged city of Homs, but relations remain fragile.
Syria's future hangs in the balance ahead of tomorrow's talks. Assad will stay, the government tells ITV News
Delegates from both sides of the Syrian conflict came to the table today but appeared no closer to finding a common position.