"The New York Times," quoting anonymous sources, reported on March 19 that Russian Security Council Secretary Igor Ivanov delivered the ultimatum to Iran's deputy chief nuclear negotiator, Ali Hosseini Tash, in Moscow last week.
Russia's Security Council has denied the report.
Tash told Iranian state radio that Russia had, on the contrary, insisted that the Bushehr issue is not linked to the standoff over the Iranian nuclear program.
The Russian state-run firm helping Iran build the Bushehr plant announced this month it was halting the planned uranium-fuel delivery because of Iran's payment delays.
Tehran ignored a February 21 deadline to suspend its uranium enrichment activities, which the West fears could be used to build nuclear weapons.
Iran insists its nuclear program is solely for energy.
(Reuters, AFP, nytimes.com)