RIYADH/AMMAN (Reuters) - Syria s main opposition group selected a new chief negotiator on Friday ahead of a new round of U.N.-backed peace negotiations with the Damascus government set to kick off next week. Nasr Hariri said the opposition was going to Geneva on Nov. 28 to hold direct talks and was ready to discuss  everything on the negotiating table . The announcement came at a summit in Riyadh where, a day before, the opposition stuck by its demand that President Bashar al-Assad play no role in an interim period, despite speculation that it could soften its stance because of Assad s battlefield strength. The opposition groups met to seek a unified position ahead of Geneva after two years of Russian military intervention that has helped Assad s government reverse major territorial losses incurred since the beginning of the war. Hariri replaces hardliner Riyad Hijab, who led the Higher Negotiations Committee at previous negotiations but abruptly quit this week, hinting that the HNC under him had faced pressures to make concessions that favored Assad. U.N. peace talks mediator Staffan de Mistura, preparing for the next round of Geneva talks, met on Friday with Russian Foreign Minister Sergey Lavrov, who said Moscow was working with Riyadh to unify the Syrian opposition. For many years, Western and Arab countries backed the opposition demand that Assad leave office. But since Russia joined the war on behalf of Assad s government it has become increasingly clear that Assad s opponents have no path to victory on the battlefield. Russian President Vladimir Putin has called for a congress of the Syrian government and opposition to draw up a framework for the future structure of the Syrian state, adopt a new constitution and hold elections under U.N. supervision.  But he has also said that any political settlement in Syria would be finalised within the Geneva peace talks process overseen by the United Nations. The opposition has long been suspicious of the parallel diplomatic track pushed by Russia, which before the proposed Sochi congress included talks in Kazakhstan, and has insisted that political dialogue should only take place in Geneva. Hariri said Sochi did not serve the political process and called on the international community, including Russia,  to concentrate all our efforts to serve the political process according to international resolutions in Geneva under UN auspices . Alaa Arafat, who represents the  Moscow Platform  political grouping, though, said he would attend Sochi and urged others to go too, reflecting lingering tensions within the diverse opposition. Saudi Foreign Minister Adel Jubeir, who opened the summit on Wednesday pledging his country s support for unifying the opposition, praised the creation of  one negotiating team that represents everyone . Asked if there was any change in position towards Assad s future, he told reporters that Riyadh continued to support a settlement based on the U.N.-backed process at Geneva.  We support the positions of the Syrian opposition. We have from the beginning and we will continue to do so,  he said. Syria s six-year-old civil war has killed hundreds of thousands of people and forced millions to flee in the worst refugee crisis since World War Two. 