TEHRAN — Mir Hossein Mousavi, a moderate politician who is considered the strongest challenger to Iranian President Mahmoud Ahmadinejad, accused him on live television June 3 of undermining the national interest by constantly questioning the Holocaust and engaging in an adventurist foreign policy.

The sharp attacks by Mousavi came during a fierce 90-minute debate with Ahmadinejad that was broadcast throughout Iran by state TV. There are no private television stations in Iran.

Mousavi accused Ahmadinejad of moving Iran towards “dictatorship” and said that the president’s foreign policy suffered from “adventurism, illusionism, exhibitionism, extremism and superficiality”. He also took issue with Ahmadinejad’s constant questioning of the Holocaust, saying that it harmed the country’s standing with the rest of the world and undermined its dignity.

“For the past four years you kept saying that the United States is collapsing, that Israel is collapsing, that France is collapsing ... Your foreign policies have been based on 'illusional perceptions'”, Mousavi charged.

Ahmadinejad, who opened the debate, presented himself as a lonely incumbent who was being challenged by a powerful circle of leaders eager to bring him down. He added that two former presidents, Ali Akbar Hashemi Rafsanjani and Mohammad Khatami, were supporting Mousavi to end his tenure.

He suggested that some leaders who opposed his policies had indulged in inappropriately lavish lifestyles. Ahmadinejad’s remarks suggested a deepening divide between the president and a number of influential leaders, including some conservatives who have been his supporters.

Support for Ahmadinejad, who is a religious conservative, appears to have weakened, and he is now widely criticised for Iran’s economic malaise.

The debate was expected to concentrate on the economy, but it devolved into a series of personal attacks. At one point, an angry Ahmadinejad pulled out a photo of Mousavi’s wife, Zahra Rahnavard, and accused her of having entered a graduate programme without taking the highly competitive entrance exam.