"Iranians have seen lots of these games," the president was quoted by state news agency IRNA as saying.

"Americans and Zionists are the sole audience of a play they have commissioned and sold out. A nauseating play is performed.

Ahmadinejad also condemned comments made by US President Barack Obama and the British government, who have lashed out at Iran.

"We have advised them repeatedly but if looks as if they insist on being humiliated, we are sure they will be humiliated more than their predecessors," he said.

Iranian Foreign Minister Manouchehr Mottaki lashed out at Britain.

"If they (the British) do not stop their absurd comments, they will be slapped in the mouth," Mottaki was quoted by the ISNA news agency as saying.

His comment came as Tehran summoned British envoy Simon Gass and as a pro-government website said a Briton was among those arrested at the demonstrations.

"The British ambassador was summoned to the foreign ministry and the Islamic Republic's protest was submitted regarding this country's interference in our internal affairs," Fars news agency said.

On Monday, British Foreign Secretary David Miliband had hailed the "great courage" of Iranian opposition supporters.

In London, the foreign office said Gass had "responded robustly... and reiterated (Miliband's) comments.

Pro-government demonstrators have reacted angrily to what they see as "desecration" of Ashura by opposition supporters and have staged counter-demonstrations calling for tough action against protesters, state media reported.

More pro-government marches are planned for Wednesday around the country.

The opposition, meanwhile, has excoriated the authorities for resorting to violence on Ashura, a day when custom prohibits it.

The Islamic Iran Participation Front, which is allied with opposition leader Mir Hossein Mousavi, called on the government to "reconcile with protesters and stop breaking the law, deception and tyranny."

On another front, Nobel peace laureate Shirin Ebadi said intelligence agents had arrested her medical professor sister, Dr Nooshin Ebadi, on Monday.

"She is not an activist and her arrest is in fact new pressure to stop my human rights work," Ebadi said in a statement on the Rahesabz opposition website.

Meanwhile, the Iranian judiciary confirmed that an Iran-based Syrian journalist for Dubai TV had been arrested on Sunday.

And in other developments, police said it was terrorists who had killed the nephew of opposition leader Mir Hossein Mousavi on Sunday in an incident unrelated to the riots that day.

On Monday the Iranian authorities said they were carrying out forensic tests on five of the eight people confirmed killed.

Tehran police headquarters said that the police forces neither used violence nor fired a single bullet on Sunday.

"Washington's behavior during the past few months was nothing but an opportunist attempt to harm the national interest of Muslim Iranians," said Larijani.

"That goes for its childish interference in our internal affairs and its duplicitous gestures on the nuclear issue," he said.

Middle East Online