Russian Energy Minister Alexander Novak discussed trade ties and investment cooperation with his Iranian counterpart Reza Ardakanian by telephone on Friday, Russia’s energy ministry said.

The ministry added that they had discussed cooperation in the energy, agricultural and transport sectors.

On Wednesday, the United States has decided to end sanctions waivers allowing Russian, Chinese and European firms to continue work at certain Iranian nuclear sites, a US official and another source familiar with the matter said on Wednesday.

The sources, who spoke on condition of anonymity, said the move applied to Iran’s Arak heavy water research reactor, the provision of enriched uranium for its Tehran Research Reactor and the transfer of spent and scrap reactor fuel abroad.

However, the sources said the United States would provide 60 days to wind down international activities – which were designed to make the Iranian nuclear program less capable of producing weapons – at the sites.