Iran's publicity loving president, Mahmoud Ahmadinejad, addresses the UN General Assembly in New York today, certain to upstage his previous visits at the annual gathering, which have been full of sound of fury. He is bearing a "message of peace and friendship with all nations", one of his aides proclaimed. But Mr Ahmadinejad leaves behind an Iran in turmoil over his disputed re-election, with hundreds of protesters and prominent reformist figures still in custody after an iron-fisted clampdown on the opposition.
Signalling that his mood will be defiant in New York - and guaranteeing a hostile reception - Mr Ahmadinejad last Friday issued his most explicit denial of the Holocaust, saying it was "a lie based on an unprovable and mythical claim". There was more defiance yesterday when Tehran boasted that it had built a new generation of centrifuges for its nuclear programme and is testing them. The unverified claim was made by the new head of Iran's Atomic Energy Organisation, Ali Akbar Salehi.
Little wonder that Barack Obama, the US president, will be on full alert for any attempt by his Iranian counterpart to ambush him with a handshake during a chance encounter in the general assembly chamber. Any photo opportunity with Mr Obama, who was to speak again at the world body today, would be portrayed by Mr Ahmadinejad's supporters as evidence of his legitimacy abroad. It would also undermine the Iranian opposition, infuriate Israel and provide Mr Obama's domestic opponents more ammunition.
Israel, meanwhile, is trying to convince delegates to the general assembly to stay away when Mr Ahmadinejad speaks. "The simple fact of leaving the room during his speech, or not to be present during it, is a symbolic act," Israel's ambassador to the UN, Gabriela Shalev, said yesterday. Mr Obama last week kept his two-year-old pledge to hold unconditional talks with Iran by accepting an Iranian offer of wide-ranging discussions on global issues, despite strident refusals by Tehran - repeated by Mr Ahmadinejad at the weekend - to curb its nuclear programme. But that does not mean a face-to-face meeting with Mr Ahmadinejad, who is toxic to American public opinion.
Instead, lower level talks on Iran's nuclear programme are to take place on October 1 between Iranian officials and envoys from the US, China, Russia, Britain, France and Germany. Mr Ahmadinejad is expected to come under heavy pressure in New York on Iran's nuclear programme, which Tehran insists is solely peaceful but the West suspects is aimed at developing a weapons capability. Mr Obama is due to hold bilateral talks with other world leaders to seek consensus before the October 1 talks. He could find the Russian president, Dmitry Medvedev, more receptive to US concerns now that he has dropped a Bush-era missile defence plan that was strongly opposed by Moscow. Russia has been opposed to new sanctions against Iran.
Iranians living in the US and Canada are determined not to let Mr Ahmadinejad use the international stage to distract from his domestic problems. Numerous protests are planned to draw attention to the ongoing repression of the opposition in Iran. Marchers plan to drape the Brooklyn Bridge with a huge green scroll, the colour of Iran's opposition movement, tomorrow. Human rights groups have called on the general assembly to appoint a special envoy to investigate post-election abuses. New York's swish Helmsely Hotel, meanwhile, cancelled a booking for a banquet after learning that Mr Ahmadinejad was to be the guest of honour.
Many American and Iran experts invited to meet the Iranian president at private functions during his previous visits to New York now see little point in repeating the exercise, believing it would send the wrong signal now. "Iranians who have had even passing contacts with American and western scholars [and many who have not] are now in jail and being forced to confess that this was all part of a plot to overthrow the Islamic Republic," Prof Gary Sick, a pre-eminent Iran expert at New York's Columbia University, wrote in his blog (http://garysick.tumblr.com/).
The Iranian president garnered widespread media coverage on his previous visits to the UN. His first trip in 2005 provoked controversy at home when he claimed that a celestial green light had surrounded him as he addressed world leaders. Last year Mr Ahmadinejad assured the general assembly that the "American empire" was nearing collapse. In 2007, he was chastised as a "petty dictator" by the head of Columbia University, where Mr Ahmadinejad stunned an audience by declaring: "In Iran we don't have homosexuals like in your country."
In the same year, the Iranian leader sat stony-faced through former US president George W Bush's address to the world body in which he denounced Iran as a "brutal" regime. When Mr Ahmadinejad made his speech a few hours later, only a note-taker was present from the US delegation. Mr Obama is expected to follow suit by skipping the Iranian president's speech today. In his 2006 speech to the general assembly, Mr Ahmadinejad lambasted Israel, saying its regime "has been a constant source of threat and insecurity in the Middle East region, waging war and spilling blood and impeding the progress of regional countries". He would be acting out of character if he does not deliver a similar rant today.
His speech is also expected to strongly defend Tehran's nuclear programme. But his words will be scrutinised closely to see whether he elaborates on a vague package of Iranian proposals to defuse the nuclear issue recently submitted to the six world powers. The proposals ignored Iran's nuclear programme, but called for global nuclear disarmament, which Iran experts say could represent an opening for talks on Iran's nuclear programme.