Iran said Monday that Saudi Arabia's plan to host a meeting of armed and political opponents of Syrian President Bashar Assad would breach declarations made during recent international peace talks.
Tehran and Riyadh are on opposite sides of the conflict in Syria but both have taken part in two major meetings in Vienna aimed at finding a political solution.
The planned meeting in Riyadh in December could boost unity in the Syrian opposition to enter talks on ending the conflict, in which 250,000 people have been killed, the U.N. envoy for Syria, Staffan de Mistura, has said.
But Hossein Amir Abdollahian, Iran's deputy foreign minister for Arab and African Affairs, slammed the planned gathering of anti-Assad political and military groups, calling it "hasty and unconstructive."
"It was agreed in Vienna that the U.N. representative in Syrian affairs try to determine a list of opposition groups by broad consultation," he was quoted as saying on state television's website.
"Tehran does not approve of measures outside this declaration."