German Foreign Minister Joschka Fischer signalled a tougher tone on Iran yesterday, warning it would be referred to the UN Security Council for possible action if it restarted nuclear enrichment.

Fischer, a key player in efforts to secure guarantees from Tehran that it will not develop an atom bomb, repeated calls for Washington to back existing European diplomacy on Iran led by Germany, France and Britain. ?If Iran were to behave unreasonably, against its own interests, if it for example restarted enrichment, ... then that would lead to the Security Council. That would be then the right church, so to speak?, he told a security conference in Munich.

Fischer did not say what action could ensue from a referral, noting there was resistance to US calls for sanctions against Tehran. Diplomats say Russia and China would oppose such a move.

The United States and Europe have failed so far to resolve their differences on how to deal with Iran and its suspected development of nuclear arms, which Tehran denies.

Washington has stressed it wants to use diplomacy over Iran but has refused to rule out military action as a last resort. The ?EU3? ? Germany, France and Britain ? have tried in talks with Iran to persuade the oil-rich country to drop its nuclear fuel-making programme in return for economic incentives.

<B>Mid-March meeting </B>

Fischer?s threat of a UN Security Council referral comes after US State Secretary Rice urged Europe to send Tehran a stronger message, but it was not clear whether it was a response to Rice?s call.

Iran suspended uranium enrichment in November as a goodwill gesture in the run-up to the talks with EU nations, but said the suspension would be a matter of months rather than years.

In Geneva, four days of closed-door discussions between the EU3 and Iran ended on Friday with an agreement to meet again in mid-March in the same Swiss city, diplomatic sources said.

European officials say the EU3?s chances of success would be greater if Washington were also to offer Tehran incentives to give up uranium enrichment, a technique which can be useful in making atom bombs, for good.

Fischer said he recognised that it was difficult for the United States to open dialogue with a nation which President George W. Bush has declared part of an ?axis of evil?, but made an new appeal for a joint approach on the problem. ?I think if the United States were to engage positively ? and I?m aware of the difficulties of doing that ? that it would substantially strengthen the EU drive?, he said.