Iran set out its position ahead of nuclear talks with world powers yesterday by saying it will never suspend its uranium enrichment programme and sees no reason to close the Fordow underground site.

Last month a senior US official said the United States and allies would demand Iran halt higher-grade enrichment and close the Fordow facility – which has been used to expand Iran's enrichment programme – at talks on May 23 over Tehran's nuclear stand-off with the West.

However, Iran's ambassador to the International Atomic Energy Agency (IAEA), Ali Asghar Soltanieh, said he saw no justification for closing Fordow, which he said was under IAEA surveillance.

"When you have a safe place under IAEA control, then why do you tell me that I should close it?" he said, making clear Iran built the site to protect its nuclear programme against Israeli or US attack. We have spent a lot of money and time to have a safe place," Mr Soltanieh added.

Iran and major powers resumed talks in mid-April in Istanbul after a gap of more than a year. They are seen as a chance to ease escalating tension and help avert the threat of a new Middle East war.

The West says Iran's nuclear work is a cover for making atomic bombs and wants verifiable assurances to the contrary from Tehran, possibly by accepting more intrusive UN inspections and limiting its uranium enrichment capacity.

Iran denies having a weapons agenda, saying it is enriching uranium for peaceful energy purposes. Refined uranium can be used to fuel nuclear power plants, which is Iran's stated aim, or provide the core for a bomb if processed more.