US President Barack Obama has urged the Iranian government to "stop all violent and unjust actions against its own people" as protests continue in Iran against the alleged rigging of last week's election.

Mr Obama said: "The Iranian government must understand that the world is watching. We mourn each and every innocent life that is lost.

"The universal rights to assembly and free speech must be respected, and the United States stands with all who seek to exercise those rights."

Meanwhile, Iran's highest legislative body says it is ready to recount a tenth of the votes in the country's disputed presidential election.

The news came as riot police were deployed to foil another planned protest rally in Tehran.

Police blocked off an area near Tehran University, where supporters of opposition candidates had intended to assemble.

But a spokesman for the Etemad-e Melli party, of losing candidate Mehdi Karoubi, said the rally had been scrapped for lack of a permit.

"Because of not obtaining permission, the rally today has been cancelled," he said.

Mr Obama has stepped up his criticism of Iran - and told its leaders the world is watching them.

The US President criticised Tehran for its violent response to a week of mass demonstrations, and insisted the protests must be allowed to proceed peacefully.

"I'm very concerned based on some of the tenor and tone of the statements that have been made and that the government of Iran recognise that the world is watching," he said.

"And how they approach and deal with people who are, through peaceful means, trying to be heard will, I think, send a pretty clear signal to the international community about what Iran is - and is not."

Iranian state media report that seven or eight people have been killed in unrest since the election result was published last Saturday.

Mr Obama has been less critical of the election than many European leaders, but the latest statement marks a clear ramping-up in tone.

It follows a speech by Iran's supreme leader Ayatollah Ali Khamenei in which he insisted last week's election was won fairly by President Mahmoud Ahmadinejad and was not rigged, as is claimed by defeated candidate Mir Hossein Mousavi.

Scores of reformists have been arrested since the election result was published on June 13, and authorities have cracked down on both foreign and domestic media.

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