UN Syria envoy Staffan de Mistura (C) welcomes those who accepted his invitation to be in Geneva, on the first day of a new round of Syria peace talks on February 23, 2017 in Geneva.

Opposing sides in the Syrian war came face-to-face in UN peace talks for the first time in three years on Thursday, to hear UN mediator Staffan de Mistura implore them to find a way out of the almost six-year-old conflict.

“I ask you to work to work together. I know it’s not going to be easy to end this horrible conflict and lay the foundation for a country at peace with itself, sovereign and unified,” Mistura told the delegates sitting opposite each other on a raised platform in a UN assembly hall in Geneva.

After his opening address, de Mistura shook hands with both sides. It was not clear when talks would resume or if the two sides would meet for direct negotiations. At the last Geneva talks, 10 months ago, de Mistura had to shuttle between the delegations who were never together in the same room.

De Mistura said the two sides had a joint responsibility to end a conflict that had killed at least 300,000 people and displaced millions.

“The Syrian people desperately all want an end to this conflict and you all know it,” he said.

“You are the first ones to tell us it. They are waiting for a relief from their own suffering and dream of a new road out of this nightmare to a new and normal future in dignity.

Describing the negotiations as an uphill task, he said they would centre on UN Security Council resolution 2254, which calls for a new constitution, UN-supervised elections and transparent and accountable governance.

He said a shaky ceasefire brokered by Russia, Turkey and Iran had opened a window of opportunity.

“The effort has jump-started the process … to see if there is a political road forward and we don’t want to miss this opportunity.”