ANKARA (Reuters) - Iran said on Thursday groups linked to Islamic State were involved in talks on forming a delegation for negotiations on the future of Syria, the semi-official Iranian news agency Fars reported.
Delegates from Syrian opposition and rebel groups agreed in Riyadh on Thursday to bring together political and armed factions in a single body in preparation for possible peace talks with the government of President Bashar al-Assad.
Iran is a crucial ally of Assad in Syria's four-year-old civil war.
"Some of the terrorist groups linked to Islamic State are involved in the (Riyadh) talks ... these terrorist groups will not be allowed to decide Syria's future," Iran's Deputy Foreign Minister Hossein Amirabdollahian said, according to Fars.
Shi'ite Muslim Iran, an arch-rival of the Sunni Muslim kingdom of Saudi Arabia, has repeatedly said the Riyadh meeting will cause the failure of negotiations intended to end the Syrian war.
The Vienna process envisages formal talks between the Syrian government and the opposition by January.
"We do not approve the Riyadh meeting ... It is not in line with the Vienna talks," Amirabdollahian said.
Writing by Parisa Hafezi; editing by Andrew Roche