The deal is expected to increase the diplomatic pressure on Iran only days after it pledged to restart its uranium enrichment program. The Tehran government has insisted its efforts are strictly focused on a civilian energy program, but the United States and others have accused Iran of pursuing a military program.
Talks headed by three European nations -- Britain, France and Germany -- stalled in recent weeks and completely derailed after Tehran's decision to end a U.N.-mandated suspension of its program.
The three negotiators, joined by other veto-wielding members of the U.N. Security Council the U.S., China and Russia, agreed to a statement expressing "serious concern over Iranian moves to restart uranium enrichment activities."
The six nations also agreed on the need for Iran to "return to full suspension," according to a statement published by the British Foreign Office.
The countries also called for an emergency meeting of the United Nation's nuclear watchdog agency, the International Atomic Energy Agency, on Feb. 2-3 to tackle the Iran issue. The 35-nation IAEA board, which could refer the issue to the Security Council, will discuss what action to take against Iran.
Despite the agreement between the six nations, they did not call for Iran to face immediate sanctions.
U.S. Secretary of State Condoleezza Rice has urged the IAEA and international leaders to press for a sanctions vote, saying a referral "ought to be as soon as possible."
"We've got to finally demonstrate to Iran that it can't with impunity just cast aside the just demands of the international community," Rice said Sunday during a trip to Africa.
But both China and Russia have been slow to criticize the Tehran government. China's Foreign Ministry, on Monday, urged in a statement, "...all relevant sides should remain restrained and stick to solving the Iranian nuclear issue through negotiations."
Although none of the communications implied Iran would face immediate sanctions, Russian President Vladimir Putin said Monday, "As for Russia, and Germany and our European partners and the United States, we have very close positions on the Iranian problem."
Even as the major nations were making their joint statements, Iran's ambassador to Russia was expressing optimism that there could still be a diplomatic solution to the standoff.
Russia has offered to aid Iran's efforts to process uranium for civilian use in Russia and then ship the fuel to Iran, therefore ensuring it is not of the quality needed for nuclear weapons production.
"As far as Russia's proposal is concerned, we consider it constructive and are carefully studying it. This is a good initiative to resolve the situation. We believe that Iran and Russia should find a way out of this jointly," Ambassador Gholamreza Ansari, said in comments translated into Russian and shown on state Channel One television.
Iranian state radio, meanwhile, reported that the government had allocated $215 million for the construction of what would be its second and third nuclear power plants. Iran has outlined an ambitious plan to build 20 more nuclear plants, many of them with Russian aid.