The Security Council resolution, which could lead to sanctions if Tehran does not comply, "shows the firm message of the international community on the Iranian nuclear issue," the foreign ministry said in a statement.

"Japan regards it as a significant step to solving the Iranian nuclear issue diplomatically," the ministry said.

It called on Iran to accept a European-led package of incentives to give up its nuclear program, saying: "Japan strongly urges Iran to return to the negotiation process."

Japan, a non-permanent member of the Security Council, voted with 13 other nations in support of the resolution, with only Qatar in opposition.

Japan is a close US ally but has also been a major investor in Iran's energy sector, as Asia's largest economy is heavily dependent on Middle Eastern oil.

In February 2004 Japan signed a deal estimated at two billion dollars to develop Azadegan, the Islamic republic's largest onshore oil field.

"The business project will not affect Japan's position towards the nuclear issue," said Chief Cabinet Secretary Shinzo Abe, the government spokesman and front-runner to be Japan's next premier.

Asked how Japan would be affected if Iran's oil exports were blocked, Industry Minister Toshihiro Nikai said, "It's not wise to make a big deal out of a hypothesis."

Japan has faced US calls to drop the Azadegan project, while Iran has warned that it could cancel the contract unless work begins soon.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.