MOSCOW, Jan. 10 (Xinhuanet) -- Russia expressed deep concern on Tuesday over Iran's resumption of research on uranium enrichment and urged it to cooperate fully with the UN nuclear watchdog to solve the dispute over its nuclear program.

    "We are very disappointed with Iran's decision to resume uranium enrichment research," the Foreign Ministry said in a statement.

    Russia calls on Iran to promptly return to the suspension of nuclear work and resume full cooperation with the International Atomic Energy Agency, the ministry said, adding suspension of nuclear work is "an essential confidence-building measure" for resolving the nuclear standoff.

    The expression of concern came after Iran removed seals of the United Nations at its Natanz nuclear research facility to pave the way for renewed nuclear work.

    Russia, which is helping Iran build its first nuclear power plant in Bushehr and has expressed interest in bidding for more nuclear work in Iran, has proposed to enrich uranium for Iran under a joint venture in Russia.

    A Russian delegation headed by Security Council Deputy Secretary Valentin Sobolev held talks with Iranian officials on Saturday and Sunday on Moscow's compromise plan.

    "Unfortunately, our Iranian partners opted for this (resumption of enrichment research) after consultations with Russian officials in Tehran on Jan. 7-8, in the course of which we persistently advised them against such a move," the ministry said.

    Iran's move is seen as likely to aggravate a confrontation with the West, which has repeatedly threatened to haul it before the UN Security Council for possible sanctions. Russia has been resisting calls for such a referral.

    The United States accuses Iran of running a covert nuclear arms program. Iran, however, says its nuclear work is designed merely to meet its energy needs and insists on the right to develop a full nuclear fuel cycle. Enditem