Last week, the Bush administration imposed new sanctions on Iran in another attempt to force the Islamic Republic to stop its nuclear weapons development program, which Iran says it needs for energy.
"I've spoken with the Russian defense minister...and I also think that the Russian willingness to support sanctions and enforce the sanctions which have been adopted is an important indicator," Senate Armed Services Committee Chairman Carl Levin said in a CBS program, "Face the Nation," on Sunday.
The senator said that Moscow is concerned about having a "rogue state" in its neighborhood that could pose a nuclear threat to Russia.
"I think it is clear and our intelligence community thinks it is very clear that Russia will not stand by while Iran has a nuclear weapon, particularly if there is any likelihood that they could threaten its use," Levin said.
Pressing for Iran to halt uranium enrichment, the UN Security Council has twice adopted sanctions against the Islamic Republic.
The new sanctions, imposed unilaterally by the United States last Thursday, target three Iranian state-owned banks, the Ministry of Defense and Armed Forces Logistics (MODAFL), nine organizations linked to the Revolutionary Guard Corps, and eight people, including three involved with Iran's Aerospace Industries Organization.
Levin said Russia would not change its moderate stance against Iran in the near future because of a number of political and economic factors.
"They're not going to go quite as far as we would, because they're playing a little bit of politics, too, with Iran," the senator said.
Russian President Vladimir Putin visited Iran on October 16 for a five-nation Caspian summit, held in Tehran.
Putin said that on the agenda during his visit to Iran were issues demanding discussion by the leaders of the two countries. Russia is building Iran's first nuclear power plant in Bushehr and Putin reaffirmed Moscow's commitment to finishing the construction on schedule, despite several delays in the past.
"We have been, and will be, building good, neighborly relations with that country [Iran]. In terms of some activities, for example, energy cooperation - oil, gas, and the electric power industry - we are very important partners," he said.
He later said at a Russia-EU summit in Lisbon that new U.S. sanctions against Iran were counterproductive and urged again the international community to seek a diplomatic solution to the Iranian crisis.
Although exasperated by the sanctions, Iran agreed in August with the International Atomic Energy Agency (IAEA) on a plan to resolve by the end of the year all outstanding issues the UN nuclear watchdog has regarding Iran's nuclear program.
Meanwhile, the IAEA head said on Sunday that he had no evidence supporting allegations that Iran was developing nuclear weapons.
"We have information that there have been maybe some studies about possible weaponization," Mohamed ElBaradei said on CNN's "Late Edition" on Sunday.
"But have we seen Iran having nuclear material that can readily be used as a weapon? No. Have we seen an active weaponization program? No," he said.
An IAEA delegation, headed by IAEA Deputy Director General Olli Heinonen, arrived in Tehran early on Monday for a fourth and final round of talks focusing on P-1 and P-2 gas centrifuges, used for the enrichment of uranium.
Iran has around 3,000 functional enrichment centrifuges at the Natanz nuclear research center. The country's leaders previously said that they intend to install 50,000 centrifuges at Natanz in a bid to make the country independent of nuclear fuel imports.
