Negotiations on Syria's conflict will move ahead as planned in Geneva, UN spokesman Ahmad Fawzi said, despite no sign that the opposition delegation will arrive.
"Talks will start as planned," Fawzi told a press conference in Geneva without giving details on the time or anything about the delegations.
UN spokeswoman Khawla Mattar said that the UN special envoy on Syria, Staffan de Mistura, will start the indirect negotiations by meeting later Friday with a delegation representing the Syrian government.
"He will continue meetings with other participants in the talks and with representatives of the civil society subsequently," she added in a statement.
The delegation is headed by Bashar Jaafari, the Syrian ambassador to the United Nations.
The UN confirmation came as opposition's negotiating team were still holding a fourth day of talks in Riyadh, Saudi Arabia, about attending the Geneva talks but has not yet made a decision.
"Our decision is still the same. We will not attend until we receive clear anwwers to our questions," Samir al-Nashar, a member of the opposition Syrian National Coalition, told dpa from Istanbul.
He said there was "tremendous pressure" from some Western powers on the opposition to go to Geneva.
Al-Nashar had earlier told dpa the opposition's Saudi-based Higher Negotiations Committee may send a smaller delegation to discuss the group's position with UN representatives.
Key members of the opposition have been indicating their participation may hinge on the Syrian government stopping airstrikes and lifting its siege on towns inside the war-ravaged country.
The UN said that 4.6 million people are stuck in Syrian areas with little or no access to aid or living in towns under siege.
De Mistura in a video message Thursday urged the sides to Syria's civil war to put an end to the bloodshed.
World powers hope that the Geneva negotiations will initiate a political process to resolve Syria's conflict that started as peaceful anti-government protests in 2011 and is estimated to have cost the lives of more than 250,000 people.
The Islamic State terrorist militia has taken advantage of Syria's strife and has seized large areas of the country.