UNITED NATIONS — As New York gears up for the U.N. General Assembly session next week, Iran’s president is honing his anti-America and anti-Israel message in what may be a ploy for attention at the annual event.

Iran has emerged as a central player in a group of countries that have turned their defiance of America into a major policy plank, and diplomats will be watching closely next week as leaders of this group, including Sudan, Venezuela, and Cuba, deliver speeches at the General Assembly. But none will be scrutinized as intensely as President Ahmadinejad.

While mainstream American politicians have ostracized him, and evangelical Christians have called for his prosecution for allegedly fomenting genocide, other Christian groups are planning to honor the Iranian leader at a dinner that will feature the new president of the General Assembly, Miguel d’Escoto Brockmann, as a speaker. And while a major protest against Mr. Ahmadinejad’s attendance at the assembly session will take place on Monday, the group Code Pink is preparing its own protest on Tuesday in front of the United Nations, where it will demand the arrest of President Bush on charges of “war crimes.”

Mr. Bush will deliver his final speech at the world body as president on Tuesday. As the annual general debate of the General Assembly opens that morning, he is scheduled to be the third speaker, after Secretary-General Ban and the president of Brazil, who traditionally opens the session. Two years ago, President Chavez of Venezuela received a standing ovation when, following a speech by Mr. Bush, he called the American leader “el Diablo.”

Despite the applause, Venezuela’s bid for a U.N. Security Council seat was rejected several months later, and many Latin American leaders cited the “Diablo” speech as a reason. While anti-Americanism may bring short-term benefits, they said at the time, it does not necessarily pay off diplomatically in the long run. Mr. Chavez did not participate in last year’s assembly gathering, and he is expected to send his foreign minister to New York next week, leaving the top seeding for anti-American rhetoric to his ally Mr. Ahmadinejad.

The Iranian leader used a Tehran press conference yesterday, on the eve of his trip to New York, to challenge the American presidential candidates to a public debate “over global issues, in the presence of the media at the U.N. headquarters.” He also said that while “some say the idea of Greater Israel has expired, I say the idea of lesser Israel has expired, too.”

In 1948, Israel cited a General Assembly resolution as one of the legal justifications for its declaration of independence. Defying a General Assembly resolution that denounces any denial of Hitler’s crimes against the Jews during World War II, Mr. Ahmadinejad yesterday called the Holocaust “fake.”

Also yesterday, the Times of London reported that Russia is planning to sell its S-300 surface-to-air missile system to Iran. “Contacts between our countries are continuing and we do not see any reason to suspend them,” the general director of Russia’s state-owned arms exporter, Rosoboronexport, Anatoly Isaikin, told the Russian news agency RIA-Novosti.

The missiles, which have a range of 90 miles, could significantly bolster Iran’s air defenses, and America has opposed their sale.

At the United Nations, Russia has been reluctant to join with America and its European allies in a resolution to impose new punitive Security Council measures against Iran for failing to suspend its nuclear program. A high-level council meeting is scheduled to take place on Tuesday, where foreign ministers will represent the 15 members of the body and discuss such issues as Sudan, Burma, and Iran. But diplomats predict no major breakthrough on any of those issues, as the council has long been divided on how to approach them.

Although the president of the General Assembly is expected to remain neutral, Mr. d’Escoto this week accused some of the five council permanent members of being addicted to war and said they have no respect for the territorial integrity of other countries.

At a press conference, a reporter noted that the assembly president must have been referring to America and the territorial integrity of Iraq, and asked whether Mr. d’Escoto, a Catholic priest and foreign minister in Nicaragua’s Sandinista government, would apply the same standard to Russia’s invasion of Georgia. “You mean Georgia’s invasion into South Ossetia,” Mr. d’Escoto retorted.