Ahrar al Sham, a major Syrian opposition faction, has signed a statement proposed by other opposition groups after pulling out of 2-day talk in Riyadh, according to a copy of the statement seen by Reuters.
The move came hours after Ahrar al Sham walked out of the meeting to protest at what it said was a lack of weight being given to "revolutionary groups" in the talks, according to a statement published on social media.
Instead, the “main role” in the talks was given to the internal political opposition group, the National Coordination Body for Democratic Change (NCB), the statement said.
Elaborating, the statement claimed that the personalities being promoted in the talks were "linked to the regime" of Bashar al Assad.
Furthermore, the faction criticised the talks for not confirming the "Muslim identity" of the Syrian people.
Ahrar al Sham called for the talks to focus on bringing Assad to justice for crimes he has committed throughout the war against his own people, and dismantling "institutions of oppression" in Syria.
Both the Free Syrian Army (FSA), one of the main opposition groups, and the Islam Army, which is led by prominent opposition figure Zahran Alloush, also joined the meeting.
Abdulaziz al-Sager, who chaired the meeting, said that an opposition delegation would meet regime representatives early next month.
"There will be a meeting decided by (United Nations envoy Staffan) de Mistura in January. A meeting between the opposition and the Syrian regime to go to a transitional period," he said, in comments translated at a news conference.
"This will take place in the first 10 days of January."
Saudi Arabia has been in touch with several Syrian opposition groups with the intention of inviting them to the talks. However, Riyadh has not invited all opposition groups to the meeting.
Monzer Akbik, a member of Syrian National Coalition (SNC), said a delegation of 20 SNC members had been invited and are planning to take part in the talks.
The SNC is the main Western-backed political opposition organisation, although it has only tenuous links with rebels on the ground and is seen as out of touch with the general population.
The Al Qaeda affiliated Nusra Front and the PKK terrorist group’s Syrian branch, the PYD, were notably omitted from the talks.
The war in Syria, which started in March 2011, has so far claimed the lives of at least 350,000 people, while displacing half of the country's pre-war population of 22 million internally and in the neighbouring countries of Turkey, Lebanon, Egypt, Iraq and Jordan.
According to Syrian Network for Human Rights (SNHR) sources, between March 2011 and October 31, 2015, more than 188,000 civilians were killed including nearly 40,000 women and children, large numbers of whom lost their lives during air strikes and barrel bombings by the Syrian regime in civilian areas.