VIENNA, Sept 20: The United States, the European Union and Russia urged Iran on Monday to comply with the UN nuclear watchdog's demand that it halt all activities linked to uranium enrichment, after Tehran rejected the call.

But Iran stood by its position, making clear it would not allow any outside interference in its nuclear activities. The International Atomic Energy Agency (IAEA) unanimously adopted a resolution on Saturday calling on Iran to suspend all activities related to uranium enrichment, a process that can be used to build an atom bomb.

But on Sunday, Iran's chief nuclear negotiator Hassan Rohani rejected the demand in the resolution, sponsored by Britain, France and Germany, and threatened to end snap checks of atomic facilities if the case was sent to the UN Security Council.

Uranium enrichment, which at a low level can be used to fuel nuclear power plants, is permitted under the nuclear Non-Proliferation Treaty (NPT). But US Energy Secretary Spencer Abraham told a meeting of IAEA members that Iran has been violating its obligations under the NPT for almost two decades by concealing its enrichment programme.

It had been "secretly building sensitive nuclear fuel cycle facilities and doing so for weapons purposes," he said. "It is essential that Iran now cooperate fully and immediately with the IAEA's requests."

The Dutch delegation chief told the meeting on behalf of the EU that the bloc "calls on Iran to heed the content of the resolution adopted by last week's (IAEA) board of governors, in particular with regard to the necessity to suspend fully all its enrichment-related activities".

The EU's "big three" powers have been trying since last year to persuade Iran to abandon its enrichment programme, which the United States and some other countries believe Tehran intends to use to make fissile material for weapons.

Iran denies that and says its nuclear programme is for the peaceful generation of electricity. Dutch ambassador Justus de Visser said of the IAEA's investigation of Iran's nuclear programme: "It is a matter of serious concern that a number of issues after two years still await clarification."

RUSSIAN CALL: In Moscow, the Russian Foreign Ministry issued a similar statement. "Tehran has been urged to re-impose a moratorium on all uranium enrichment activities. We back this call," it said.