Officials from the five permanent members of the UN Security Council are due to meet in London to discuss a third set of sanctions against Iran.

Iran refuses to stop enriching uranium, as demanded by council resolutions.

The US, Britain and France pushed for a third resolution but were blocked by China and Russia earlier this year.

Iran insists its nuclear program is entirely peaceful. Some Western powers accuse Iran of trying develop a nuclear weapon.

In September, the permanent Security Council members agreed to delay a vote on further measures until the publication of a report in mid-November on Iran's activities by the UN nuclear watchdog, the International Atomic Energy Agency.

'Years from bomb'

On Tuesday the US and France dismissed a statement by the IAEA head Mohammed ElBaradei that there is no evidence of Iran building a bomb.

French Defense Minister Herve Morin challenged Iran to allow UN inspectors unlimited access to sites.

US officials said Iran's efforts to enrich uranium rather than import it more cheaply, indicated that it really wanted nuclear weapons.

Mr ElBaradei said on Sunday that Tehran was years away from developing a bomb.

The IAEA has some access to Iranian nuclear facilities but Tehran's refusal to allow intrusive inspections means the UN cannot verify the absence of undeclared nuclear material.

There is tension between Western countries and Mr ElBaradei over an agreement he reached with Iran in August, drawing up a timetable for the country to answer questions about its past nuclear activities.

Mr ElBaradei says he will report to the IAEA's board in mid-November on how much information Iran has provided.

PHOTO CAPTION

Bushehr nuclear reactor