President Mahmoud Ahmadinejad of Iran has written to President Bush proposing "new solutions" to their differences in the first letter from an Iranian leader to an American president since the Iran hostage crisis 27 years ago.

A government spokesman, Gholam-Hossein Elham, said today that the letter was sent via the Swiss Embassy in Tehran which has a US interests section. It was written ahead of a meeting of major powers in New York that will see Margaret Beckett, the new British Foreign Secretary, thrown into the deep end of international politics.

In the letter, Mr Ahmadinejad proposes "new solutions for getting out of international problems and current fragile situation of the world", Mr Elham said. The spokesman said did not mention the nuclear dispute, the major issue on which Washington and Tehran are at loggerheads.

The United States is backing an Anglo-French draft resolution at the UN Security Council censuring Iran for refusing to cease enrichment of uranium - an activity that Tehran says is strictly for the generation of nuclear power, but which Washington believes is an attempt to develop nuclear weapons.

On her maiden trip as Foreign Secretary, Mrs Beckett will meet her counterparts from the four other permanent members of the UN Security Council — and Germany — who are locked in bitter dispute over how to proceed on the Iranian nuclear issue.

Over the weekend Russia and China made clear their opposition to the draft resolution proposed by Britain and France to force Iran to halt its uranium enrichment work or the nuclear ambitions of Iran.

Iran threatened to quit the Nuclear Non-Proliferation Treaty (NPT), which controls the spread of nuclear technology, if the UN acted against it. The talks tonight — over a dinner that Condoleezza Rice, the US Secretary of State, will host — are the culmination of months of delicate diplomacy that Jack Straw, the former Foreign Secretary, was instrumental in developing.

The draft resolution is under Chapter VII of the UN Charter, making its demands binding. If Tehran did not comply, it would face the threat of sanctions or military force in a follow-up resolution.

The Bush Administration wants to force a vote on the resolution this week, with or without consensus among all 15 members of the Security Council. Nine votes in favour are needed to pass a resolution, but Russia and China have the right of veto. "We are still working to achieve unanimity . . . but we are prepared to go to a vote without it," John Bolton, the US Ambassador to the UN, said.

Moscow and Beijing are resisting any move that could lead to economic sanctions. Sergei Kislyak, the Russian Deputy Foreign Minister, said that the Anglo-French draft required "major changes" before it would be acceptable to the Kremlin.

Iran showed no sign of halting its uranium enrichment work, and President Ahmadinejad vowed yesterday to ignore any UN action. "They should know that the Iranians will dash their illegitimate resolution against the wall," he said.

His letter to Mr Bush is the first by any Iranian president to his US counterpart since 1979, when the two countries broke relations after Iranian militants stormed the US Embassy in Tehran and held 52 diplomats and staff hostage for more than a year.

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