Senior officials from permanent UN Security Council members Russia, China, France, Britain, and the United States, plus Germany, are in attendance.
Ahead of today's meeting, Iranian President Mahmud Ahmadinejad warned that Tehran would consider any move against its nuclear interests as a "hostile" act.
"If you continue making efforts to halt the progress of Iran's nuclear program [or] if you take any step against Iran's rights -- either in propaganda or international bodies -- the Iranian nation will consider this a hostile act," Ahmadinejad told an audience in the northern Mazandaran Province.
Russia has so far objected to tough sanctions to punish Tehran for its refusal to meet an August 31 UN deadline to abandon uranium enrichment.
French Foreign Minister Philippe Douste-Blazy said after talking with his Russian counterpart, Sergei Lavrov, on December 4 that progress had been made on the wording of a sanctions resolution.
U.S. Undersecretary of State Nicholas Burns said the same day that deliberations among the major powers on what to do about Iran had been going on for far too long. U.S. President George W. Bush has vowed not to allow Iran to develop nuclear weapons, calling such a scenario "unacceptable."
Burns said he was not expecting any breakthrough in today's talks. He urged Russia and China to move closer to the U.S. and European positions on how best to convince Iran to abandon any ambitions to make nuclear weapons.
Foreign Minister Lavrov said ahead of today's meeting that imposing broad sanctions against Iran to punish Tehran for pursuing uranium enrichment would be "irresponsible" and counterproductive. He reiterated Russian support for limited sanctions, saying any other strategy would achieve "opposite results."
Officials in Tehran have repeatedly countered that their nuclear program is solely peaceful.
The UN nuclear watchdog, the International Atomic Energy Agency (IAEA), has criticized Iran for obfuscation and has said it has not been convinced that the country's nuclear efforts are not aimed at developing weapons.
Economic sanctions could further undermine Iran's already shaky economy (Fars)
MOVING TOWARD SANCTIONS: If the United Nations Security Council imposes sanctions on Iran, domestic support for Iranian President Mahmud Ahmadinejad will wane, according to ALEX VATANKA, Eurasia editor for Jane's Information Group.
Vatanka told a February 24 RFE/RL briefing that "economic sanctions will hurt the average Iranian" and, consequently, many "will blame the ruling clerics" for making life difficult and "impairing the country's long term development."
Vatanka said sanctions would be a serious challenge to the Iranian government. If harsh economic sanctions were imposed, Iran's poorest population will be hurt the hardest -- and might react "as they did in the 1970s and protest in the streets." Sanctions on travel, Vatanka said, would hurt a many Iranians because "Iran is a nation of small traders" who depend on the ability to travel to earn an income. According to Vatanka, unemployment in Iran is estimated at 30 percent, "so small trading is essential to survival." Although current U.S. sanctions "haven't worked," he said, "Iranians fear an oil embargo." He stressed that "oil revenues are a major part of the economy, so it is critical to look at this sector."
Should negotiations with the European Union and the UN fail, Vatanka believes that Iran would follow a "North Korea model," since Ahmadinejad's base of support among the "Islamist militias" has been "urging withdrawal from the NPT [Nuclear Non-Proliferation Treaty]." The Iranian government's "tactic" so far, Vatanka said, is governed by the belief that "by shouting the loudest, you'll get concessions [from the West]."
Listen to the complete panel discussion (about 60 minutes):
THE COMPLETE STORY: RFE/RL's coverage of the controversy surrounding Iran's nuclear program.
CHRONOLOGY An annotated timeline of Iran's nuclear program.