Tehran  - Iran is now operating more than 5,000 centrifuges for enriching uranium as it continues to move forward on developing a nuclear capability in defiance of the United Nations, the country's nuclear chief said Wednesday.

"Currently we have more than 5,000 centrifuges operating," Gholam- Reza Aqazadeh, head of Iran's Atomic Energy Organisation said, according to the official IRNA news agency.

The United States and its allies suspect Iran is seeking the ability to build nuclear weapons, and the UN Security Council has adopted three resolutions containing limited sanctions and demanding Tehran suspend uranium enrichment.

"Suspension has no meaning at all in Iran's culture and no such a thing exists," Aqazadeh was quoted as saying.

Iran insists the programme is solely for producing civilian nuclear energy. Uranium enriched at low levels is used to produce nuclear fuel but enrichment at higher grades make it suitable for nuclear weapons.

US Secretary of State Condoleezza Rice would not comment on the scale of Iran's centrifuge process, instead awaiting a confirmation for the UN nuclear monitoring body called the International Atomic Energy Agency.

"The point is that they are continuing to pursue enrichment and reprocessing capability," Rice said. "They are continuing to try to perfect the technologies that could lead to a nuclear weapons technology."

President Mahmoud Ahmadinejad had also said in July that of 6,000 new centrifuges, 5,000 have become operational and the then-deputy foreign minister, Alireza Sheikh-Attar, who is now Iran's ambassador to Berlin, said later in August that Tehran is planning to install 54,000 centrifuges.

The IAEA has so far confirmed that about 3,000 to 3,500 centrifuges were operational at the Natanz plant. Iranian claims of the number of centrifuges often do not match IAEA reports.

In his latest report on Iran to member states, IAEA Director General Mohamed ElBaradei said that "regrettably, as a result of the lack of cooperation by Iran in connection with the alleged studies and other associated key remaining issues of serious concern, the agency has not been able to make substantive progress on these issues."

Aqazadeh told Khabar news network, "We have had and will have our normal cooperation with the IAEA but what Mr ElBaradei indicated in his report goes back to terms within the (IAEA) Additional Protocol."

Iran's cooperation with the IAEA in the last three years has solely been within the Nuclear Non-Proliferation Treaty (NPT) and not the IAEA Additional Protocol, and therefore Tehran does not allow the IAEA to have any inspections without prior notice or venues outside NPT obligations.

"For implementing the Additional Protocol, the necessary political conditions should be provided accordingly. But currently, with the Iranian nuclear dossier at the UN Security Council, these conditions are not given," said Aqazadeh, who is also vice president.

Tehran demands the return of its nuclear dossier from the UN Security Council to the IAEA in Vienna and that it be dealt with as a normal case.

The IAEA has received documents from a number of member states indicating that past Iranian projects on missiles, high explosives and uranium conversion could have been related to nuclear weapons work.

Tehran however says that Iran is not in charge of following allegations made by other member states, especially as no documented proof has yet been presented.

Iran further says that numerous inspections by the IAEA have proved Iran's claim that its nuclear projects were solely for peaceful and civil purposes and Tehran, as NPT signatory, should therefore be allowed to follow a civil nuclear programme, including uranium enrichment. (dpa)