Syria's government has threatened to walk out of peace talks with the opposition if the two sides do not begin what it called "serious sessions" by Saturday.
The ultimatum, aired on Syrian state television, came as the two parties failed to meet face-to-face, as expected, Friday, the first day of formal peace talks in Geneva.
A senior U.S. State Department official says that "contrary to reports, the Geneva talks have not been canceled." He said United Nations peace mediator Lakhdar Brahimi still plans to hold a trilateral meeting, but has delayed it to allow for more preparation.
Government and rebel representatives are meeting in separate rooms, with Brahimi shuttling back and forth.
The rival delegations have shown no sign of compromise and both have threatened to pull out of the long-delayed talks, which began Wednesday with feisty opening statements in Montreux.
The opposition says it will not negotiate directly with the Syrian government, unless it agrees to discuss the departure of President Bashar al-Assad. Damascus has refused, accusing the rebels of supporting terrorism.
Syrian National Coalition President Ahmad Jarba on Thursday declared there should be no doubt the Syrian "regime is dead." But he said it is important the talks move forward.
"The negotiations will be difficult. There is no easy negotiation. But the road of one thousand miles starts with one step."
The official goal of the so-called Geneva 2 talks is to form a Syrian transition government, though analysts say the chances of achieving this goal are slim. Instead, more modest achievements, such as allowing humanitarian aid to civilians, are expected.
The Syrian conflict began in March 2011 as peaceful protests before spiraling into a civil war that the U.N. says has killed well over 100,000 people and forced nearly 9 million from their homes.