The UN special envoy for Syria has announced the official start of peace talks between the Syrian government and opposition leaders.
Staffan di Mistura spoke after hosting envoys from the main Syrian opposition group at the UN offices in Geneva.
He had previously met a government delegation on Friday.
Mr di Mistura laid out the positions of the opposition group.
He said he planned to take up further talks in a new meeting with government representatives on Tuesday, and his first goal is to keep the talks going.
The talks are aimed at ending a five-year conflict that has killed 250,000 people and displaced millions, leaving vast areas of the country in ruins.
They have been slow in starting, largely because of disputes over which opposition groups can take part and opposition demands that the government allow aid into besieged rebel-held areas and halt its bombardments of civilians before the talks start.
“We have come to Geneva to seek relief for our people by insisting UN Security Council resolution 2254 is implemented, which means humanitarian relief, the lifting of sieges, and the end of attacks on civilians,” opposition spokesman Salem al-Mislet said in a statement.
The talks are part of a process outlined in last month’s UN resolution that envisions an 18-month timetable for a political transition, including the drafting of a new constitution and elections.
In Jordan, UK Foreign Secretary Philip Hammond said: “We expect both sides to participate in these talks in Geneva in good faith, and finally to provide the peace that the Syrian people deserve.”
Mr Hammond, who said Britain backs the moderate opposition, called for “complete and unfettered humanitarian access across Syria and an end to all violations of international humanitarian law, including the indiscriminate bombing of civilian populations”.
"Long on talk, short on peace" - Will Syria peace talks face a similar fate as the Oslo accords? https://t.co/EzE2BsgvW1 by @MarwanBishara
— Al Jazeera English (@AJEnglish) January 31, 2016