Reformist movements in Iran are hoping to carry out more rallies to protest a disputed election that has triggered the most serious unrest in the country since the 1979 Islamic revolution.
Groups backing reformist Mir Hossein Mousavi, the top rival to re-elected President Mahmoud Ahmadinejad, have asked Iran's Interior Ministry for permission to hold demonstrations on Wednesday.
In enormous mass rallies Tuesday in Tehran, large groups supported either Mr. Ahmadinejad or Mr. Mousavi.
Authorities tightened restrictions on foreign news organizations Tuesday, banning reporters and photographers from covering demonstrations.
Iran's powerful Guardian Council said Tuesday it will recount some ballots from Friday's controversial vote after challengers to President Ahmadinejad called his re-election a fraud.
In Washington, U.S. President Barack Obama said he is greatly concerned about the dispute over Iran's presidential election and the suppression of peaceful dissent in Tehran. Mr. Obama also said the U.S. will not intervene in Iran's political dispute, because that would be meddling, and the Iranian people must decide how to resolve the situation.
The president also said there appears to be little difference in policy between the conservative Mr. Ahmadinejad and Mr. Mousavi, a reformist.
Mr. Obama discussed the situation in Iran with reporters at the White House, and in a series of interviews.
Whether Mr. Ahmadinejad or Mr. Mousavi prevails when the results of Iran's election are re-examined, Mr. Obama told one of his interviewers the United States will be dealing with a regime that is hostile to Washington.
Aides to two prominent reformist politicians, Saeed Hajjarian and Mohammed Ali Abtahi, say they were detained on Tuesday. Abtahi is an assistant to former Iranian President Mohammad Khatami. Separate reports say 26 people with ties to the violence in Tehran have been arrested.
Iranian state media also reported that seven people were killed Monday when reformists attacked a Tehran office of the Basij, a pro-government militia. Witnesses circulated video showing that militiamen opened fire on the protesters.
Government officials say Mr. Ahmadinejad won re-election with 63 percent of the ballots last Friday, compared to 34 percent for Mr. Mousavi.
Iran's state-run Press TV said Tuesday that a parliamentary committee is investigating the post-election disturbances.
Some information for this report was provided by AP and Reuters.