"The activities are continuing," said foreign ministry spokesman Mohammad Ali Hosseini, responding to media speculation that its enrichment work at a plant in central Iran had slowed or even come to a halt.

Iran has declared the installation of two cascades of 164 centrifuges apiece at the plant in Natanz and expressed a wish to have a total of 3,000 centrifuges in place by March this year.

Officials have also indicated that the Islamic republic will make a major announcement over its nuclear programme during festivities to mark the 28th anniversary of the Islamic revolution in February.

The UN Security Council in its December resolution once again demanded that Iran halts uranium enrichment, a highly sensitive process that can be used both to make nuclear energy and a nuclear bomb.

Iran insists that its nuclear programme is entirely peaceful.