MOSCOW, September 28 (RIA Novosti) - The international community could still tighten sanctions against Iran, a senior member of the Russian parliament said on Monday.

Iran told the International Atomic Energy Agency last week about a partially-built second uranium enrichment facility. France said Iran would face more sanctions if its leaders did not review their policy by the December deadline.

"If one has to choose between war and tighter sanctions, the latter is preferable," said Mikhail Margelov, the head of the upper house's international affairs committee.

He added that although Moscow does not believe in the effectiveness of sanctions - be it against Iran or any other country - "in some situations, sanctions become inevitable."

He said it was not so much about "sanctions per se as a signal that they will send to the Iranian leadership."

Russia has repeatedly stressed the diplomatic approach over further sanctions in international efforts to allay concerns over Iran's nuclear program, but President Dmitry Medvedev sounded more open to the idea during last week's trip to the United States.

"Sanctions are not the best way to deal successfully with Iran, but if we run out of all other options, we could launch sanctions based on international law," Medvedev said in an address to students and professors at the University of Pennsylvania.

Iran is under three sets of UN Security Council sanctions over refusal to halt uranium enrichment, needed both for electricity generation and weapons production.

Iran's underground uranium enrichment center in Natanz, subject to UN inspections, has over 8,300 centrifuges and is expanding rapidly. Iranian authorities have repeatedly said the country needs 50,000 centrifuges to supply its future nuclear power plants with fuel.