The sense of threat against the opposition was growing. Reuters reported that Mohammadreza Habibi, the senior prosecutor in the central province of Isfahan, had warned demonstrators that they could be executed under Islamic law. It was not clear if his warning applied only to Isfahan or the country.

The Associated Press reported that the powerful Revolutionary Guards threatened restrictions on the digital online media that many Iranians use to communicate among themselves and to send news of their protests overseas. In a statement, the Revolutionary Guards said Iranian website operators and bloggers must remove content deemed to “create tension” or face legal action.

In Paris, Soazig Dollet, a spokeswoman for Reporters Without Borders, a press freedom advocacy group, said at least 11 reporters had been arrested.

Government officials telephoned or sent faxes to reporters in Tehran working for foreign news organisations ordering them not to venture outside to cover events being held without an official permit. That included rallies by supporters of Moussavi. At least one newspaper has stopped printing.

Defying restrictions, new amateur video surfaced outside of Iran on Wednesday, apparently showing a government militia rampaging through a dormitory area of Tehran University late Tuesday or early Wednesday.

Support for the protests came from some unusual quarters. Five Iranian soccer players, including the captain, Ali Karimi, wore green wristbands in an apparent sign of support for Moussavi at a World Cup Asian qualifying match in S Korea, the AP said.

The Fars news agency reported that the partial recount of votes ordered on Tuesday by the Guardian Council, the 12-member body of jurists which supervises elections, had begun.