The US and other Western nations are planning to demand that Iran immediately close and ultimately dismantle a recently completed nuclear facility deep under a mountain as part of new talks with Iran over its nuclear programme, the New York Times has reported.

The Obama administration and its European allies will also call for a halt in the production of higher-level enrichment of
uranium fuel, and the shipment of existing stockpiles of that fuel out of Iran, the US-based newspaper said on Sunday, citing US and European diplomats.

The diplomats said they could not imagine any agreement that left Iran with a stockpile of fuel, enriched to 20 per cent purity, that could be converted to the grade needed to make an atomic bomb in a matter of months.

"We have no idea how the Iranians will react," a senior Obama administration official told the newspaper. "We probably won't know after the first meeting."

The opening talks have been tentatively set for Friday.

  Click for more on Iran's nuclear facilities

In January, major powers signalled willingness to reopen the talks about curbing Iran's suspected pursuit of nuclear weapons but said Tehran must show it was serious about negotiations.

Iran says its nuclear programme is aimed solely at generating power.

The US, Britain, France, Russia, China and Germany are the six powers involved in diplomacy aimed at resolving the long-running dispute over Iran's atomic plans.

Russia and China recently joined the four Western powers in expressing "regret" over Iran's expansion of higher-grade enrichment, most of which is now taking place deep inside a mountain near the holy city of Qom.

The focus on diplomacy followed rising tensions between the West, which is seeking to cut Iran's oil sales, and the Islamic republic, which threatened to close the Strait of Hormuz through which almost one-fifth of oil traded worldwide flows.

The US has gradually tightened sanctions on Tehran due to its failure to answer questions about its nuclear programme.

Source: Agencies