The informal meeting at Britain's UN mission in New York brought together envoys of Germany and the five veto-wielding members of the UN Security Council -- Britain, China, France, Russia and the United States.
The diplomats made no comment as they headed into a new round of bargaining on a draft resolution put forward by Britain, France and Germany, which have unsuccessfully been trying to persuade Tehran to scale down its nuclear ambitions.
The text calls for a series of nuclear- and ballistic-missile-related trade sanctions, a freeze on assets related to Iran's nuclear and missile programs and travel bans on scientists involved in those programs.
But it would allow Russia to continue building a one-billion-dollar nuclear power plant in the Iranian city of Bushehr -- an exemption that diplomats say is crucial to efforts to gain Moscow's approval.
The sponsors were keen to hear from Russian ambassador Vitaly Churkin, who, according to diplomats, returned from Moscow on Thursday with instructions on how to respond to the draft.
A diplomatic source said Russia wanted the sponsors to drop any reference to Bushehr from the draft and to remove the travel ban and assets freeze.
The Russians will support only a ban on "sensitive (nuclear) technologies", he added.
In Moscow, Russian deputy foreign minister Sergei Kisliak also made it clear on Friday that Russia remained firmly opposed to the European draft as it currently stands.
"We can't support it in its current form," he told the Interfax news agency.
The informal discussions were suspended a week ago, with Russia and China still reluctant to agree tough sanctions against a country with which they have close energy and trade ties.
Washington, meanwhile, views the European proposals as not going far enough.
Iran faces sanctions after spurning an earlier Security Council resolution mandating a freeze on its uranium enrichment program -- a process that can eventually provide fissile material for nuclear weapons.
Tehran insists the program is only geared toward generating electricity.
The six powers have offered Tehran a package of economic and diplomatic incentives if it gives up the enrichment program.
On Tuesday, US Secretary of State Condoleezza Rice called her five counterparts to urge speedy passage of the sanctions resolution, and on Thursday she warned that inaction was not an option.
"I think the Iranians are a threat, and that's why the international community's got to be strong in resisting their ambitions," she said.
Rice also responded to the first launch by Iran on Thursday of a new long-range ballistic missile, the Shahab-3, during war games seen as a warning to the West over the nuclear showdown.
"They're trying to say to the world, 'You're not going to keep us from getting a nuclear weapon.' The world has to say to them, 'Yes, we will,'" Rice said in a radio interview.
"But the Iranians also, I think, are not unaware that the security environment is one in which, if they actually were to do something, Iran would suffer greatly, and so I think they probably understand that," she added.
The European sponsors plan to circulate their draft to the council's 10 non-permanent members early next week.
And diplomats say they anticipate protracted and tough haggling before an acceptable draft can be agreed.

Copyright AFP (Agence France-Presse), 2006