Russia has called on Iran to explain reports from the International Atomic Energy Agency (IAEA) that suggest Tehran is building a nuclear warhead, the Interfax news agency reported Friday.
"Iran must rebut this suspicion," Russian Foreign Ministry spokesman Andrei Nesterenko said, DPA reported.
On Thursday, the IAEA said for the first time that it had concerns Iran was currently working on a warhead.
The ministry called on Iran to cooperate with the agency, as well as with the six-nation group that have been attempting to negotiate with Tehran on its nuclear programme.
Russia has not ruled out giving its assent on the United Nations Security Council to further sanctions on Iran.