“The issue of Iran is key for us,” Russian news agencies quoted Foreign Minister Sergei Lavrov as saying while on a visit to France. 

“Iran without question is one of the most important nations,” he said in Paris. 

Russia has argued that both Iran – a key backer of Syria – and opposition ally Saudi Arabia should take part in the negotiations as part of a new push for peace agreed by Moscow and Washington earlier this month. 

France has already rejected the idea of Iran taking part while the United States has responded to Moscow’s proposal with skepticism. 

The proposed conference to try to end two years of conflict in Syria could take place over the weekend of June 15-16 in Geneva, diplomatic sources said on Tuesday, according to the Associated Press.

Lavrov said that he and US Secretary of State John Kerry had agreed in Paris on Monday that more “clarity” was needed about who could take part in the proposed negotiations before a date for them could be set.

“We must get clarity about the participants,” said Lavrov. “And this concerns not only the Syrians that will represent the various levels of society, but also the foreign players.”

Russian officials had earlier Tuesday denied that a specific date for the conference was already being decided.

Various media reports have suggested that the talks might begin in the week starting June 10.