Before Iran's disputed June 12 vote, Mr. Obama had made several modest overtures toward Iran and made clear his hope that 30 years of bitter hostility can be overcome. But Obama this week said he was "appalled and outraged" by a crackdown on protests against widespread fraud in Iran that have officially left 20 dead.
The hard-line Mr. Ahmadinejad – who, in his first four year term, mixed harsh criticism of Washington's policies with praise for "noble Americans" – accused Obama of echoing former US President George W. Bush.
"Mr. Obama made a mistake to say those things ... our question is why he fell into this trap and said things that previously Bush used to say," Ahmadinejad said, according to the Fars news agency, which is linked to Iran's Revolutionary Guards.
"I hope you avoid interfering in Iran's affairs and express your regret in a way that the Iranian nation is informed of it," Ahmadinejad added.
Majority of lawmakers skip Ahmadinejad's victory bash
Iranian officials have charged that the US, Britain, and Israel are behind demonstrations that have brought hundreds of thousands out onto the streets – resulting in clashes, street violence, and rioting – in a bid to annul Ahmadinejad's unexpected 2-to-1 landslide victory over Mir Hossein Mousavi.
American officials said on Wednesday they had withdrawn invitations to Iranian diplomats to attend July 4 festivities at US embassies around the world – one US step that Washington had hoped would help break the ice. No Iranian official had accepted the invitations anyway, according to the State Department.
The crisis has exposed further divisions within Iran's ruling elite. Local newspapers reported that only 105 out of the 290 members of parliament (MPs) attended a victory celebration for Ahmadinejad, with the majority skipping the event. [Editor's note: The original version reversed the proportion of lawmakers who attended to those who did not attend.]
Mr. Mousavi has not been seen in public for many days, as riot police and armed militiamen have battled protesters or prevented them from gathering. In a message on Mousavi's website Thursday, he said his access to people was now "completely restricted" and that he had been under "pressure" to give up his challenge.
"I cannot modify black as white and white as black," he was quoted as saying, according to the Associated Press. "This is not the solution, to expect me to express something which I don't believe."
70 professors detained
Some 70 professors were reportedly detained after meeting with Mousavi, during which he criticized Iran's supreme religious leader and said the "government will face a crisis of political legitimacy," Mousavi's Website stated, in a translation by the Guardian newspaper in London. The Guardian later reported that all but four of the 40 were released, quoting a "reliable source" from the New York-based group Human Rights Watch.
In a second statement on Thursday, according to the Guardian, Mousavi said he would not keep quiet: "I am ready to show how the electoral wrong-doers, standing beside the main agitators that have caused the present disturbances, have spilled people's blood."
He called on supporters to resist calmly. "[The people's] problem is with millions of votes whose fate is unknown," Mousavi said. "It is a must for us to neutralize this evil conspiracy through our behavior and expressions."
State-run English language Press TV reported that Mousavi and the head of Iran's Expediency Council, Ali Akbar Hashemi Rafsanjani – one of Mousavi's key backers – both met with the governing board of parliament's national security committee and promised to help end unrest.
Charges by Mousavi that the crisis had harmed the "legitimacy" of Iran's Islamic system of rule have been echoed by Iran's most important dissident cleric, who was once the chosen successor to rule Iran after Ayatollah Ruhollah Khomeini, until a falling-out in 1989 over human rights issues.
"If Iranians cannot talk about their legitimate rights at peaceful gatherings and are instead suppressed, complexities will build up which could possibly uproot the foundations of the government, no matter how powerful," Grand Ayatollah Hossein Ali Montazeri said in a statement to Agence France-Presse.
Grand Ayatollah Montazeri called for an "impartial" committee to be appointed to resolve the crisis.