The Russian foreign minister said it was “of principal importance to maintain and boost the presence of IAEA inspectors and monitors in Iran.”

“They currently work at all nuclear objects of Iran and have uncovered no illicit activities so far,” Lavrov added.

He said that the sanctions against Iran should be lifted only after Tehran eases international concerns about its nuclear program.

"The six nations’ approach, voiced several years ago, stipulates that as soon as Iran persuades the world community via the IAEA verification that its nuclear program is absolutely peaceful by nature, it will be vested with all the rights of an IAEA nuclear member state,” Lavrov said.

"All variants concerning Iran are being studied, but we will accept only those allowed by international law and the UN Charter,” Lavrov said.

The Iran Six has been trying to convince Iran to halt its uranium enrichment program and to alleviate concerns about its nuclear ambitions since 2003. Talks were suspended in 2009 after the IAEA accused Iran of building undeclared nuclear facilities.

Iran is already the subject of a wide range of international sanctions because the West, led by the United States, accuses Tehran of pursuing a secret nuclear weapons program. However, the Islamic Republic insists its nuclear power needs are for civilian purposes only.

The Islamic Republic has recently announced its readiness to reopen talks with members of the so-called Iran Six or P5+1 group, which comprises the United States, Britain, France, Germany, Russia and China, on April 13 in Turkey.