There "seems to be no agreement" on two key issues just hours before the latest international conference on Syria is held Friday in New York, Iran's foreign minister said.

Mohammad Javad Zarif told The Associated Press on Thursday that his country has seen "no lists we can agree upon" of Syrian opposition groups that should be included in peace negotiations set to begin by Jan. 1, or of Syrian groups that should be considered terrorist organizations instead.

"Card-carrying members of al-Qaeda do not satisfy the conditions that we set for members of the opposition," Zarif told reporters, ruling out any affiliates of the extremist group. "The opposition should be serious, and it should be inclusive."

Zarif also said "we still don't know" if there will be any concrete progress in the talks that are aimed at bringing an end to Syria's conflict. Iran, a top Syria ally, will attend.

Russia and the United States are leading the talks, but Russia's ambassador to the UN told reporters that he sees attempts to "undercut" the communiques that have been agreed upon in the Syria discussions so far. Ambassador Vitaly Churkin didn't give details.

A peace plan agreed to last month by 20 nations meeting in Vienna sets a Jan. 1 deadline for the start of negotiations between Assad's government and opposition groups. The plan says nothing about Assad's future but says that "free and fair elections would be held pursuant to the new constitution within 18 months."

Diplomats said the five permanent UN Security Council members, which include Russia and the United States, had not yet come to agreement on a draft resolution Thursday evening that the council is expected to adopt just after Friday's talks endorsing the process.

"I'm not sure it's going to happen," Churkin said of the resolution, which has been described as a rare gesture of unity in a Security Council that has been bitterly divided on Syria.

By contrast, British Ambassador Matthew Rycroft said the draft was "in good shape."

Russia, a top Syria ally, and the West continue to be split on the central issue in any discussions on a political transition: the fate of Syrian President Bashar Assad.