Dozens of Syrian opposition groups and factions gathered in a meeting held at Riyadh, the capital of the staunch ally of the groups, Saudi Arabia, to forge a unified front against Syrian President Bashar Assad, whose fate is going to be discussed by world powers in Vienna in January.

Most of the main opposition groups participated in peace talks for the first time since the beginning of the almost five-year-long crisis and getting rid of Assad, who has been given a new lease of life by Russian and Iranian intervention, is crucial for the groups.

The most salient group among the participants, Ahrar al-Sham, said on Wednesday that the meeting must insist that Assad face justice and that Syria's "institutions of oppression" are dismantled. Together with Ahrar al-Sham, there are Western-backed opposition groups, the Syrian National Coalition, and the Syria-based National Coordination Body, as well as groups like the Western-backed Free Syrian Army and the Saudi-backed Jaysh al-Islam.

It is reported that Al-Qaida's affiliate in Syria, the al-Nusra Front, and the PKK's Syrian-affiliate, the People's Protection Units (YPG), have not been invited to Riyadh. The Syrian Democratic Forces, a recently formed alliance of the YPG and smaller Arab and Christian militias was also not invited.

The main Western-backed political alliance, the National Coalition for Syrian Revolutionary and Opposition Forces, which was created in Doha in November 2012, will send 20 delegates to Riyadh. Recognized by 120 countries as the representative of the Syrian people, it participated in two rounds of peace talks in Geneva with regime delegates in 2013 and 2014. The coalition supports the implementation of the 2012 Geneva Communique, which calls for the establishment of a transitional governing body in Syria. The Turkey-based group led by Khaled Khoja insists that Assad must go.

The Syria-based opposition grouping, the National Co-ordination Committee for Democratic Change, calls for negotiations on a peaceful transition. Although tolerated by the government, its members have been harassed and detained. One of the co-founders of the group, Haytham Manaa, a longtime dissident, said that it would send 20 delegates to the meeting.

The secular grouping of figures from across the political spectrum was represented in talks in Moscow and presents itself as an alternative to the National Coalition, though it has not been recognized as such.
Along with the future anti-Assad stance, the meeting is also considered crucial for eliminating DAESH, which has undermined opposition groups through constantly-organized attacks in their fight against Assad.

On a visit to Irbil in the north of Iraq Tuesday, German Foreign Minister Frank-Walter Steinmeier called on the splintered Syrian opposition to overcome their differences during the coming days of Vienna talks and said, "I hope that it will be possible in Riyadh for the Syrian opposition to agree on a common stance for negotiations on a transitional government with the government in Damascus, even if that will require some difficult compromises."

"We must not lose the momentum generated by the two conferences in Vienna in efforts to end the civil war and violence. It is therefore important that we meet again in the near future in the Vienna format and take the next steps together with all stakeholders at the table," Steinmeier said.

The Syrian civil war erupted in 2011 during a government crackdown on protests against Assad. About a quarter of a million people have been killed in the conflict, according to estimates by the United Nations.