Former Iranian President Mohammad Khatami is hosting a high-profile conference uniting former U.N. chief Kofi Annan and other dignitaries this week — a rare visit seen as a reformist effort to position him for a comeback ahead of crucial elections.

Long an opponent of hardline President Mahmoud Ahmadinejad, Khatami has stepped up his criticism in recent months. And he is under increasing pressure from moderates to challenge Ahmadinejad in June's presidential elections.

Khatami's supporters believe a victory by a political moderate would help Iran out of international isolation.

But Khatami insists he has made no decision and reacted angrily when asked whether the high-profile visitors reflected backing for a possible presidential bid.

"This conference has nothing to do with presidential elections," Khatami chided reporters. "Don't undermine this conference by such speculations."

Reformists are eager to interpret the presence of former world leaders — including former Irish President Mary Robinson, and the former prime ministers of Italy and France, Romano Prodi and Lionel Jospin — as a gesture of support for Khatami.

The European dignitaries reportedly had no plans to meet with Ahmadinejad while in Iran. Annan met the Iranian president separately Monday afternoon.

The June vote is critical for Ahmadinejad, who was elected in 2005 promising to improve the lives of ordinary Iranians but has since last year faced increasing criticism for his failure to do so.

Under Ahmadinejad, Iran has suffered international isolation, skyrocketing prices and even threats, from the U.S. and Israel, of military strikes to halt Iran's nuclear program which the West fears lead to an atomic bomb.

On Saturday, one of Ahmadinejad's top advisers, Mahdi Kalhor, told the official Iranian News Agency, Iran would only hold talks with the U.S. only if its forces leave the Middle East and Washington ends its support for Israel.

Khatami is seen by many moderates and reformers as Iran's best chance at ending the country's isolation.

Eight months before the vote, Iran's reformists are adamant Khatami should run.

"Our homeland Iran is in danger. Khatami has to run in the upcoming elections to save Iran from catastrophe and destruction," said prominent reformist Mostafa Tajzadeh.

"The current situation in Iran has made it difficult for Khatami to reject demands to run in the upcoming elections. His language also shows that he is thinking about it more seriously than before," Tajzadeh said.

Iran's former vice president, Majid Ansari, also believes recent developments indicate Khatami is preparing to run.

"It is now more likely that Khatami will run for president next year," Ansari told The Associated Press.

Khatami's guests declined to comment on his possible candidacy, apparently unwilling to have Ahmadinejad's supporters accuse them of interfering in Iran's internal affairs.

Other prominent figures at the venue included former Portuguese President Jorge Sampaio, Sri Lankan ex-President Chandrika Kumaratunga, Sudan's former Prime Minister Sadeq al-Mahdi and former UNESCO director general Federico Mayor.

Khatami is hosting the two-day conference, which ends Tuesday, as the head of the International Institute of Dialogue among Cultures and Civilizations. It explores religious and cultural concepts and rejects extremism.

Following the conference, Annan and several others among the visiting dignitaries will make a trip on Tuesday evening and Wednesday to Yazd, Khatami's birthplace in central Iran.