Iran clarified on Tuesday that its offer of allowing "full supervision" of its atomic programme in return for lifting of sanctions does not include snap checks by UN inspectors of its nuclear units.

On Monday, Iran nuclear chief Fereydoun Abbasi Davani, told the ISNA news agency that Tehran was prepared to give the International Atomic Energy Agency "full supervision" of its controversial nuclear programme for five years if UN sanctions are lifted.

On Tuesday ISNA asked him whether this offer includes the implementation of the additional protocol of the nuclear Non-Proliferation Treaty, which calls for tougher and snap inspections of atomic activities of its signatories.

Abbasi Davani said the offer does not include such inspections of Iran's nuclear facilities.

"We will not accept any more obligations," he told ISNA.

"We have always had full cooperation with the agency," Abbasi Davani said, adding that Iran's cooperation is "within the standards and regulations" of the UN nuclear watchdog.

The Iranian proposal was immediately rejected Monday as insufficient by the European Union, which said the Islamic republic must first re-establish confidence for any sanctions to be lifted.

"Iran still has to comply with its international obligations, despite today's announcement," Michael Mann, spokesman for EU foreign policy chief Catherine Ashton, told AFP.

Ashton has made a "concrete proposal" to Iran aimed at building confidence over the aims of its atomic programme, Mann said. "Unfortunately, so far, Iran has not taken up this offer to enter into meaningful talks."

"Existing UNSC (UN Security Council) resolutions foresee the lifting of sanctions once confidence has been re-established," he said.

Iran is targeted by four sets of UN Security Council sanctions over its refusal to suspend uranium enrichment amid fears in the West that it seeks to build a nuclear bomb -- a charge it vehemently denies.

Much of Iran's nuclear activities are already under the control of the IAEA, including uranium enrichment -- a process which can produce the fuel for a nuclear reactor and also the fissile material for an atomic warhead.