Thousands of supporters of Iran's defeated presidential candidate Mirhossein Mousavi marched in Tehran today following a disputed poll prompting the biggest street protests since the 1979 Islamic revolution.
On a fourth day of demonstrations since Friday's election, witnesses said they headed - largely in silence without the accustomed chants - towards the state television building, despite Mousavi's call for them to call off a planned rally.
In what appeared to be a first concession by authorities to the protest movement in the world's fifth-biggest oil exporter, Iran's top legislative body said it was prepared for a partial recount but ruled out annulling the poll.
The decision was taken by the 12-man Guardian Council following the election in which hardline President Mahmoud Ahmadinejad was declared the runaway winner.
In an apparent attempt to deny the opposition the chance to keep up the momentum of mass street protests, Ahmadinejad's supporters mobilised thousands of demonstrators in central Tehran where Mousavi's supporters had planned to gather again.
The Mousavi supporters marching today said they planned to assemble in front of the state television IRIB building in northern Tehran. Witnesses said some supporters had already gathered close to the building, which was ringed by riot police.
Wearing wristbands and ribbons in his green campaign colours, Mousavi supporters carried his picture and made victory signs. Mousavi has disputed official results of the poll.
Unlike Monday's vast opposition march in central Tehran, in which seven people were killed, they largely refrained from chanting anti-Ahmadinejad slogans.
State television said the "main agents" in post-election unrest had been arrested with explosives and guns.
US President Barack Obama, who has sought to engage Iran and asked its leadership to "unclench its fist", reacted today to Iran's post-election violence by saying he believed "people's voices should be heard and not suppressed".
Mr Obama also said he did not want to be seen as "meddling" in Iranian internal affairs.
The United States and its European allies have found Mr Ahmadinejad implacable in asserting Iran's right to enrich uranium, a programme that Iran says is purely peaceful but that they fear could be used to make a nuclear bomb.
Iranian authorities had banned today's opposition rally and state television showed live pictures of thousands of Ahmadinejad supporters, some waving Iranian flags, gathering at Vali-ye Asr Square where Mr Mousavi supporters had planned to go.
At the rally, a former parliamentary speaker, Gholamali Haddadadel, drew cheers by saying that Tehran, where Mr Mousavi won the most votes, did not represent all of Iran. He added: "I would like to tell Mr Mousavi:... Before the election was held it was not right for people close to you to say that if you see Mr Ahmadinejad victorious there has been electoral fraud."
Mr Mousavi had urged his supporters to stay away from the square "to protect lives".
Further protests, especially if they are on the same scale as yesterday's, would be a direct challenge to the authorities who have kept a tight grip on dissent since the US-backed shah was overthrown in 1979 after months of demonstrations.
Discord within Iran's ruling system has never been so public. The Mousavi camp is backed by traditional establishment figures, such as former presidents Akbar Hashemi Rafsanjani and Mohammad Khatami, concerned about how Mr Ahmadinejad's truculent foreign policy and populist economics are shaping Iran's future.
Supreme Leader Ayatollah Ali Khamenei, supposedly above the political fray, has favoured Ahmadinejad, who is also supported by the elite Revolutionary Guard and the Basij militia.
Intelligence Minister Gholamhossein Mohseni-Ejei said his ministry was chasing two types of people over the unrest.
"One wanted to achieve its goal through explosions and terror, and in this connection 50 people were arrested and more than 20 explosive consignments were discovered. They were supported from outside the country," he told state radio.
"The second category was made up of counter-revolutionary groups who had penetrated election headquarters (of the election candidates) ... Some 26 such elements have been arrested," he added. Iran often accuses Western foes of stirring instability.
Illustrating Iran's sensitivity to world opinion, authorities today banned foreign journalists from leaving their offices to cover street protests.
France, Germany and Britain have led an EU campaign to persuade Iran to clarify the election results, but Iran today summoned a Czech diplomat, representing the EU, to protest against "interventionist and insulting" EU statements.
A spokesman for the Guardian Council, which groups clerics and Islamic law experts as a constitutional watchdog, said that it was "ready to recount the disputed ballot boxes claimed by some candidates, in the presence of their representatives".
"It is possible that there may be some changes in the tally after the recount," spokesman Abbasali Kadkhodai said.
"Based on the law, the demand of those candidates for the cancellation of the vote - this cannot be considered," he told state television.
Despite the turmoil, Mr Ahmadinejad travelled to Russia for a summit of the Shanghai Cooperation Organisation, which includes Russia and China, where he was congratulated on his re-election.
Reuters