"If we achieve what we want in the negotiations, then the fight is over, if we fail, then the people of arms will continue to bear them and to push on the path to victory," Alloush, who is a former chief negotiator for the High Negotiation Committee (HNC), told the Anadolu news agency in an interview.
He stressed that the negotiations climate has improved considerably due the participation of Russia.
Alloush added that it was "impossible to strive for the endless war" and that the opposition was seeking to end the bloodshed.
The Syrian government and opposition factions are expected to meet in Astana on January 23 for talks brokered by Russia, Turkey and Iran, which will be followed by a UN-mediated meeting in Geneva on February 8.
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