TEHRAN (Reuters) - Police clashed with supporters of Iran's opposition leader Mirhossein Mousavi in Tehran on Wednesday when a rally marking the 30th anniversary of the storming of the U.S. embassy turned violent, witnesses said.
Reformist website Mowjcamp said police opened fire on protesters at Haft-e Tir square, but there was no independent confirmation. "Some people were injured," Mowjcamp said, reporting protests elsewhere such as the central city of Shiraz.
Iran's Revolutionary Guards and their allied Basij militia had warned the opposition to avoid using anti-U.S. rallies to revive protests against the clerical establishment after June's disputed presidential election.
"Police clashed with hundreds of protesters. They were chanting: 'Death to dictators'. Police used batons to disperse them," a witness said. People traditionally chant, "Death to America" to mark the anniversary.
President Mahmoud Ahmadinejad, locked in a row with the West over Iran's nuclear programme, won a second term. Washington says Iran seeks a nuclear weapon, a charge Tehran denies, and has threatened more sanctions through the United Nations.
The turmoil after the June vote was the worst in Iran since protests which led to the ouster of the U.S.-backed Shah three decades ago. Authorities deny vote-rigging and portrayed the unrest as a foreign-backed bid to undermine the Islamic state.
Thousands of Iranian security forces assembled on the streets of Tehran on Wednesday to prevent opposition rallies and rein in political dissent.
Opposition leaders Mousavi and Mehdi Karoubi, who both ran against Ahmadinejad, had urged their supporters to take to the streets to protest against his government despite warnings from the Iranian police about "illegal gatherings."
Mowjcamp said Karoubi joined the protest on Wednesday. "He is walking towards the former American embassy," the site said.
Another witness said police fired teargas at the crowd and arrested at least five protesters.
"There are hundreds, chanting 'God is greatest'. Police and Basij militia are outnumbering the protesters," one witness said. "Hundreds of police, riot police, Basij militia and plainclothes are in the main squares," another said.
OFFICIAL RALLY
Thousands of people also gathered in front of the former U.S. embassy for an official ceremony where influential lawmaker Gholamali Haddadadel criticised the opposition leaders.
"I don't know how they (opposition leaders) are going to answer to the great Iranian nation. They claim they are followers of the revolution but issue statements that are in the interests of Iran's enemies," he said in a speech.
Haddadadel said the U.S. administration should change its policy towards Iran's nuclear energy programme: "No one in Iran can make a deal on Iran's obvious right to nuclear technology."
U.S. President Barack Obama used the anniversary of the hostage crisis to urge Tehran to make concessions over its nuclear programme, saying it needs to turn the page on the past and forge a new relationship with the United States.
"Iran must choose," Obama said. "We have heard for 30 years what the Iranian government is against; the question, now, is what kind of future it is for."
Protesters carried banners saying "We are ready to sacrifice our blood for (Supreme Leader Ayatollah Ali) Khamenei," and "Death to America" and "Death to Israel."
Anti-Western rallies usually take place outside the building -- now called the "den of espionage" in Iran -- to mark the anniversary of the day in 1979 that the embassy was seized.
During the Iranian revolution, militants stormed the embassy on November 4, 1979 and held 52 Americans hostage for 444 days.
Protesters in the opposition camp targeted other foreign countries too. Some reformist websites called on people to gather outside the Russian embassy, in an apparent protest at Moscow's recognition of Ahmadinejad's re-election on June 12.
"Dozens of police and Basij forces are around the Russian embassy as well," one witness said. Another witness said dozens of police were walking around the British embassy in Tehran.
In September, opposition demonstrators clashed with government backers and police at annual pro-Palestinian rallies.
(Writing by Parisa Hafezi; editing by Peter Millership)
