The European Union said it was disappointed after talks with Iran on Friday seen as a last chance to avert US pressure for tougher international sanctions over Tehran's disputed atomic programme.
The absence of a breakthrough at the London talks means six world powers meeting in Paris on Saturday will try to agree new penalties to propose to the United Nations, despite differences in their approach to halting Iran's nuclear programme.
"I have to admit that after five hours of meetings I expected more. I am disappointed," EU foreign policy chief Javier Solana told reporters, adding he would meet Iran's negotiator Saeed Jalili again before the end of December.
Jalili told reporters after the meeting it was "unacceptable" to demand Iran halt its uranium enrichment programme and that any new UN sanctions would fail to prevent Tehran from pursuing its atomic work.
"If some countries want to use the UN Security Council and its resolutions to stop Iran's atomic work, surely they will not be successful," Jalili said. The West says the programme is aimed at building atom bombs and wants Iran to freeze its enrichment of uranium. Iran, a major oil exporter, says enrichment efforts are meant only to produce electricity which it says is an inalienable right.
Attempts by the six nations - Britain, China, France, Germany, Russia and the United States - to stall Iran's programme have failed and they vowed to pass a new UN Security Council resolution if there was no progress by December.
Asked whether Iran had brought any new initiatives to the table on Friday, Solana's spokeswoman said: "Not enough new in order not to be disappointed." The five permanent members of the Security Council plus Germany plan to draft a new resolution imposing wider financial, trade and visa restrictions to increase pressure on Tehran to stop enriching uranium, which can be used in atomic bombs.
But the six powers remain at odds over how soon to resort to more United Nations penalties, or how harsh they should be.
Russia and China, and to a lesser extent Germany, have close commercial ties with Iran and are likely to tailor their new sanctions proposals accordingly, taking a less hawkish approach than that of the United States, Britain and France.
Iranian Foreign Minister Manouchehr Mottaki said late on Thursday that nothing would deflect Iran from its pursuit of nuclear technology and that Washington had "lost".
"The Iranian nation will never return from the path that they have chosen and they are determined and decisive to continue this path (to obtain nuclear technology)," Mottaki was quoted as saying by the official IRNA news agency.
"America is angry with Iran over its nuclear programme but they know that the cost of attacking Iran will be very high," Mottaki told a gathering of the Basij religious militia. "America has lost in its nuclear challenge with Iran."
Jalili replaced Ali Larijani as chief nuclear negotiator in October. Close to President Mahmoud Ahmadinejad, he is seen by analysts as signalling a hardening of Iran's position.
"They (Western countries) shouldn't make threats because threats make Iran more determined," former president Akbar Hashemi Rafsanjani told worshippers at Tehran University. Rafsanjani, who is also the speaker of the powerful Assembly of Experts, said Iran was co-operating with the International Atomic Energy Agency (IAEA), referring to an August agreement under which Tehran pledged to the Vienna-based body to clear up suspicions about past secret atomic activities.
Iran has barred inspections beyond uranium production sites since its case was referred to the UN Security Council in February 2006, fuelling suspicions in the West that it has a covert parallel military nuclear programme.
The IAEA sees wide-ranging access to Iran's sites, provided for under the IAEA's Additional Protocol with member states, as key to verifying there is no such programme. "Iran has no programme to discuss the Additional Protocol at its parliament and Iran has no commitment regarding the implementation of the Additional Protocol," Mottaki said.