Iran pledged yesterday to accelerate cooperation with the UN atomic watchdog in a bid to prove it is not seeking nuclear weapons, but also pressed to end UN inspections by June.

Mohamed ElBaradei, head of the International Atomic Energy Agency (IAEA), said Iran had agreed to a timetable for atomic checks and to submit full details of its nuclear programme and ambitions to the IAEA in mid-May.

"(Iranian nuclear chief Gholamreza Aghazadeh) committed that Iran will do everything possible to accelerate the process of resolving the outstanding issues," Mr ElBaradei told reporters after talks in Tehran.

The IAEA is seeking clarification of how traces of weapons-grade uranium came to be found at the Natanz enrichment plant south of Tehran and a Kalaye Electric Company workshop.

If enriched to a low level, uranium can be used to fuel nuclear power stations. But further enrichment can make it suitable for use in warheads.

The United States accuses Iran of pursuing a nuclear weapons programme, but Tehran says its nuclear ambitions are confined to generating electricity. Hawks in Washington are seeking to get the UN Security Council to impose sanctions against Iran.

Tehran promised Britain, France and Germany last October it would suspend uranium enrichment and accept snap atomic checks.

The IAEA also wants answers on Iran's omissions of key atomic technology from an October statement that included undeclared research on advanced "P2" centrifuges that can make weapons-grade uranium.

In a show of goodwill, Mr Aghazadeh said Iran would suspend the making and assembling atomic parts from Friday, something it agreed to do by March under an arrangement struck in February.