Iran is close to acquiring the capability to make nuclear weapons, Russian President Dmitry Medvedev warned on Monday.

He urged Russian ambassadors and permanent representatives to move away from "simplistic approaches" toward the Iranian nuclear problem, adding that nuclear weapons capability is not prohibited by the Nuclear Nonproliferation Treaty.

He reiterated Russia's position that sanctions "are not producing the desired results" but admitted that Iran was "not behaving in the best manner."

On June 9, the UN Security Council passed Resolution 1929 imposing a fourth set of sanctions on Iran over its nuclear program, including tougher financial controls and an expanded arms embargo.

"We are consistently urging Tehran to show the necessary openness and cooperation with the International Atomic Energy Association," the Russian president said.

He said the main goal of the latest UN resolution on Tehran was to restart the negotiation process as soon as possible.

"If diplomacy misses this chance, it will be a collective failure," Medvedev said.

MOSCOW, July 12 (RIA Novosti)