TEHRAN - Iranian authorities on Sunday blamed terrorists for clashes in which at least 10 people were killed and President Mahmoud Ahmadinejad told the West to stay out of unrest sparked by his disputed re-election.

EDITORS' NOTE: Reuters and other foreign media are subject to Iranian restrictions on their ability to report, film or take pictures in Tehran.

In a sign of increased opposition among clerics to the Islamic Republic's leadership, Mohammad Khatami, a moderate former president, warned that banning protests in support of defeated presidential candidate Mirhossein Mousavi was a dangerous move.

Preventing people from expressing their demands through civil ways will have dangerous consequences (for the country), Khatami, a Mousavi ally, said in a statement, the semi-official Mehr news agency reported.

Iran state television said 10 people were killed and more than 100 others injured in protests held in Tehran on Saturday in defiance of a stern warning by Supreme Leader Ayatollah Ali Khamenei. A separate report put the number of deaths at 13.

State television said the violence included the torching of a mosque, which it blamed on rioters.

In the unrest leading to clashes 10 people were killed and more than 100 wounded, it said. The presence of terrorists ... in yesterday's event in Enghelab and Azadi avenues was tangible.

The harshness of the language suggested the authorities may be preparing for a crackdown to end more than a week of protest.

The disputed June 12 election handed an overwhelming victory to the hardline, anti-Western Ahmadinejad sparking the biggest protests and most violent unrest since the 1979 Islamic Revolution which ousted the U.S.-backed shah.

Mousavi, who came second to Ahmadinejad in the poll and whose followers have spearheaded protests, says the election was rigged and must be annulled.

WEST ACCUSED

State television suggested that only the West stood to gain from the unrest and Ahmadinejad accused Washington and London of interfering in Iran's affairs.

I advise you (the United States and Britain) to correct your interfering stances, Ahmadinejad was quoted by ISNA news agency as saying at a meeting with clerics and scholars.

U.S. President Barack Obama, in the forefront of diplomatic efforts to halt an Iranian nuclear program the West fears could yield atomic weapons, urged Tehran to stop all violent and unjust actions against its own people.

The Iranian government must understand that the world is watching. We mourn each and every innocent life that is lost, Obama said in a statement.

British Foreign Secretary David Miliband rejected Ahmadinejad's charge. The UK is categorical that it is for the Iranian people to choose their government, he said.

German Chancellor Angela Merkel, in a statement, urged the Iranian leadership to allow peaceful protests and conduct a recount of votes cast in the election.

There were no immediate reports of protests in Tehran on Sunday. Government restrictions prevent correspondents working for foreign media from attending demonstrations to report.

Riot police were deployed in force on Saturday, firing teargas and using batons and water cannon to disperse groups of several hundred Iranians who had gathered across the city.

CLERIC CRITICISES

The most senior dissident cleric, Grand Ayatollah Hossein Ali Montazeri, added his voice to critics of the leadership, calling for three days of national mourning for those killed, a statement on his website said.

Resisting people's demand is religiously prohibited, said Montazeri, an architect of Iran's 1979 Islamic revolution who fell out with the present leadership and has been under house arrest for some years.

The hard-hitting statements by Khatami and Montazeri signaled increased opposition to Khamenei's approval of the official election result.

State TV announced the arrests of members of the Mujahideen Khalq Organization (MKO), an exiled opposition group which it accused of terrorist activities including setting buses on fire and destroying public property.

The daughter of former President Akbar Hashemi Rafsanjani -- a rival of Ahmadinejad -- was also among those detained during an opposition rally in Tehran on Saturday, Fars news agency, citing a security official, said. She appeared to have been later released.

The authorities reject charges of election fraud. But the highest legislative body has said it is ready to recount a random 10 percent of votes cast.

Khatami was skeptical. Referring the dispute to a body which has not been impartial regarding the vote, is not a solution, he said in a statement, Mehr reported.

Mousavi on Saturday said the Islamic Republic must be purged of lies and deviations and told supporters he was ready for martyrdom, according to an ally. But he said he did not seek confrontation with the authorities.

In Paris, European Central Bank President Jean-Claude Trichet said tensions in Iran had added to risks facing the world economy and underlined the need for strengthening the global financial system.

Any additional geo-strategic tension is obviously an extra risk for the international economy, he told Europe 1 radio.

In London, the BBC confirmed that Iran had ordered the broadcaster's correspondent, Jon Leyne, out of the country.

(Additional reporting by Fredrik Dahl and Zahra Hosseinian, James McKenzie in Paris, Brian Rohan in Berlin; Writing by Richard Balmforth; Editing by Jon Hemming)