Kharazi, who arrived in Japan late Wednesday after trips to India and China, handed over a letter from President Mohammad Khatami to Japanese Prime Minister Junichiro Koizumi about the sensitive nuclear issue.

The visit came after a confidential UN report said inspectors found two different types of highly-enriched nuclear particles at facilities in Iran that were not needed in civilian atomic programmes.

The findings were contained in a report by the International Atomic Energy Agency that was handed to the nuclear watchdog's board of governors Tuesday ahead of a crucial meeting on Iran, a Western diplomat in Vienna told AFP.

Kharazi was quoted by the official as telling Koizumi that the letter from Khatami carried Iran's basic policy on the nuclear issue and contained two main points.

"One is our plan to enhance cooperation with the IAEA and the other is our decision to launch negotiations towards signing an additional protocol," to the nuclear Non-Proliferation Treaty (NPT), the minister was quoted as saying.

The protocol paves the way for surprise inspections of nuclear sites.

"Iran will secure transparency and offer constructive cooperation with the IAEA," the minister was quoted as saying.

"We hope the IAEA will make a professional judgment without being used for political purposes."

IAEA spokesman Mark Gwozdecky told AFP on Tuesday Iran had signalled it was ready to move towards signing the additional protocol.

Koizumi and Kharazi did not discuss a multi-billion dollar deal to develop the massive Azadegan oil field, situated in the southwest of the Islamic republic, the Japanese official said.