The two sides have agreed that the agenda should include four topics: combatting violence, transitional government, national institutions and national reconciliation, UN mediator Lakhdar Brahimi told a news conference on Saturday.

But they have not agreed on the order in which the topics will be discussed. Brahimi proposed devoting the first day to a discussion of violence and “terrorism,” and the second to the issue of a transitional governing body.

“I apologise to the Syrian people … I apologise to them that in these two rounds we haven’t helped them very much,” Brahimi said.

He urged both sides to “reflect” and return ready to make progress in the anticipated third round.

Al Jazeera’s James Bays, reporting from Geneva, said the government and opposition spoke for less than 30 minutes before talks ended on Saturday.

“It was a short, tense session, dominated by differences over how to tackle the issues of violence and political transition,” opposition negotiator Ahmad Jakal told the Reuters news agency.

“[UN mediator Lakhdar] Brahimi set no date for a third round but he made it clear he expects there will be one,” he said.

Mounting carnage

A Syrian activist group, meanwhile, says the death toll in Syria’s three-year-old civil war has reached 140,000.

The Britain-based Syrian Observatory for Human Rights said on Saturday that the dead include civilians, rebels, members of the military, pro-government militiamen and foreign fighters.

The group bases its count on a network of informants on the ground.

The UN’s human rights office, however, has stopped updating the death toll from Syria’s civil war, saying it can no longer verify the sources of information that led to its last count of at least 100,000 last summer.