Iran on Wednesday rejected a call by world powers for more nuclear talks with their envoy and said it would in future discuss its uranium enrichment programme only with the UN nuclear watchdog.
Tehran also brushed off a third round of sanctions imposed on it on Monday by the UN Security Council over its refusal to suspend enrichment, saying its economy would not be affected.
In Vienna, Britain, France and Germany told governors of the International Atomic Energy Agency that Iran's record of cooperation with IAEA inspectors was "abysmal" - a much harsher judgment than that reached by the watchdog itself.
The IAEA wants to learn the true scope of Iran's nuclear programme. A Feb 22 IAEA report said improved Iranian cooperation had helped inspectors resolve all but one question about its past work, but Iran had not explained intelligence on alleged explosives and missile studies applicable to atom bombs.
The three EU powers sponsored more extensive Security Council sanctions imposed on the Islamic Republic on Monday.
They, together with the United States, Russia and China, also said they wanted EU foreign policy chief Javier Solana to meet Iran's chief nuclear negotiator, Saeed Jalili, to try to reopen talks on offers of incentives for Iran to halt its work.
Iranian President Mahmoud Ahmadinejad rejected the idea.
"From now on, our nuclear issue is with the agency (IAEA) only and we will not negotiate with anyone outside the agency about Iran's nuclear issue," the official IRNA news agency quoted him as saying in his first reaction to new sanctions.
A senior Iranian official said Ahmadinejad meant Tehran would accept no more talks with the EU based on their demand for a nuclear halt in exchange for trade benefits and a halt to sanctions. "This carrot and stick policy does not work with us. So they should review their policy," he told Reuters.
Iran was, however, ready to discuss issues such as regional security, trade or nuclear power plants, said the official, who asked not to be named due to political sensitivities.
At the IAEA board of governors meeting, the "EU-3" countries cast the recent agency report on Iran in a more negative light.
IAEA Director Mohamed ElBaradei had said only one issue of nuclear proliferation concern remained to be clarified, and the rest were "no longer outstanding" - a position he said was "obviously encouraging."
"(ElBaradei's) report leaves our three countries in no doubt that Iran's record in complying with these requirements remains abysmal," the three said in a speech presented by British IAEA Ambassador Simon Smith to the 35-nation board.
An IAEA briefing for diplomats last week, highlighting intelligence about nuclear "weaponisation" work Iran has dismissed as fabricated, underlined Tehran's "record of delay and obfuscation" in dealing with IAEA inquiries, Smith said.
"As long as Iran's choice remains one of non-cooperation, we for our part will remain determined to demonstrate the costs and consequences of that choice," he added, alluding to sanctions.
The Islamic Republic's IAEA ambassador said the latest Security Council sanctions would have no effect on Iran's "exclusively peaceful nuclear activities".
But most on the 35-nation IAEA Board, while recognising that information Iran had provided had eased some concerns about past activity, said Tehran had much more to do to clean its slate.
They pointed in particular to intelligence data, much of it from a laptop smuggled out of Iran by a defector, suggesting links between processing uranium for nuclear fuel, testing high explosives and modifying a missile cone for an atomic payload.
In Geneva, Foreign Minister Manouchehr Mottaki said the new sanctions would not affect the Iranian economy. "Within the last year we have signed and concluded economic contracts with so many companies from around the world," he told reporters.
Asian and other firms continue to sign energy deals with Iran. But European executives say it has become increasingly difficult for Iranian firms and their Western partners to open letters of credit for imports into the country.