TEHRAN: Police used batons and teargas to break up an opposition protest in central Tehran on Wednesday, while huge crowds staged a noisy anti-US rally nearby to mark the storming of the American embassy by students 30 years ago.

US President Barack Obama, meanwhile, in a statement marking the anniversary of the event that sparked decades of hostility between America and Iran urged Tehran to make choices that would end its international isolation.

Witnesses said the violent clashes occurred at Haft-e-Tir square in the heart of the capital when riot police armed with batons and firing teargas moved in on a crowd of several hundred opposition supporters staging a protest.

The protesters, who were chanting ‘Death to the dictator,’ refused to disperse and dozens were beaten or arrested. Groups of pro-government hardliners also gathered at the square chanting ‘Death to America.’ Opposition website Mowzcamp.com reported that opposition leader Mehdi Karroubi was among the protesters at the square but left quickly after he and his supporters came under attack by the hardliners.

The report could not immediately be confirmed.

Away from Haft-e-Tir square, opposition supporters — numbering several thousand in all — gathered in small groups on many street corners and side roads, witnesses said.

Staging brief demonstrations during which they chanted ‘Death to the dictator,’ and ‘Ya Hossein, Mir Hossein’ — in praise of main opposition leader Mir Hossein Moussavi — the mainly-young protesters quickly moved on to new sites when police tried to disperse them.

Witnesses said the entire city centre had become a stage for ‘cat and mouse games’ between police on bikes and youthful protesters.

According to the Irna news agency, protesters set fire to rubbish bins and attacked a bus, smashing its windows. It said two policemen were injured in the clashes and hospitalised.

Opposition supporters have since June been staging protests at every opportunity in Tehran against the re-election of Mahmoud Ahmadinejad in a presidential vote they claim was massively rigged.

About a kilometre away, outside the former US embassy complex — dubbed the ‘Den of Spies’ — thousands of Iranians gathered from early morning chanting slogans such as ‘Death to America’ and ‘Death to Israel,’ witnesses said.

They also smashed up posters they had brought with them of the American ‘Uncle Sam’ symbol and chanted ‘The blood in our veins is a gift to our leader’— a reference to Iranian supreme leader Ayatollah Ali Khamenei.

The crowd was constantly swelled by people arriving on foot and by bus, witnesses said.

By mid-afternoon the streets of Tehran were calm again as people who took part in the various rallies and protests went home, witnesses said. However, a large security force presence remained on standby in the city centre.

Wednesday’s anniversary, which has turned into a cornerstone of the Islamic regime, marks the capture by radical Islamist students of the US embassy compound on November 4, 1979 — just months after the Islamic revolution toppled the US-backed shah.— AFP