The UN chief is planning the controversial stop in Teheran next week over strenuous American objections, even though the Iranian leader has urged the destruction of another UN member state.

The world’s top diplomat wants to visit Iran as part of a diplomatic swing through the Middle East to pin down a peace deal on Lebanon.

Syria, currently under UN investigation for the assassination of the former Lebanese prime minister Rafik Hariri, is also on his tentative itinerary.

A US official said Washington had made clear to Mr Annan that it did not want him to visit Iran or Syria.

Mr Annan was forced to cancel a scheduled trip to Iran last November after the newly elected Iranian President first called for the elimination of Israel.

His decision was heavily influenced by a personal appeal from US Congressman Tom Lantos, a personal friend who was saved from the Nazi Holocaust by Swedish diplomat Raoul Wallenberg, the uncle of Mr Annan’s wife.

At the time, Mr Annan said he had read President Ahmadinejad’s comments “with dismay.”

He pointed out that “under the United Nations Charter, all members have undertaken to refrain from the threat or use of force against the territorial integrity or political independence of any state.”

UN aides have urged Mr Annan to make the trip to Syria and Iran in the face of American complaints, even though both countries are the subject of Security Council scrutiny.

The 15-nation council has ordered a halt in arms shipments to Hezbollah, which both Syria and Iran supply.

Syria has been implicated by a Security Council-mandated investigation into the bomb blast that killed Mr Hariri in February 2005.

Iran is facing the threat of UN sanctions if it fails to meet a Security Council deadline of next Thursday to stop enriching uranium in what the West fears is part of a clandestine nuclear weapons programme.

Although the focus of the trip is Lebanon, Western diplomats are concerned that Mr Annan should not offer Iran concessions in its nuclear stand-off with the UN.

Britain, along with France, Germany and the United States, are lobbying him to stand firm in urging Iranian compliance with the Security Council’s demand for a suspension of uranium enrichment work. “If he gives the wrong message that would be worrying,” one senior diplomat said.

The Tehran trip represents a diplomatic gamble by Mr Annan with just four months left in office after two five-year terms.

Some diplomats and UN insiders fear the trip could be a replay of Mr Annan’s 1998 trip to Iraq, which prompted him to say he could “do business”, with then Iraqi President Saddam Hussein.

Mr Annan also plans to stop in Israel, Lebanon, Turkey, Egypt, Jordan and Qatar after attending an EU foreign ministers’ meeting on Lebanon in Brussels on Friday.

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