Tens of thousands of Iranians chanting anti-US slogans took to streets of Tehran on Tuesday for a mass rally marking 30 years since the Islamic revolution toppled the US-backed shah.

Men and women with children in tow walked towards Azadi (Freedom) Square to join members of the Basij Islamist militia for the annual demonstration at a time of continuing tense relations between Tehran and Washington.

Demonstrators carried placards saying "30 years of freedom, 30 years of pride", "Death to America", "Death to Israel" and balloons in the colours of the Iranian flag.

The United States and other world powers suspect Iran''s controversial nuclear programme is aimed at making atomic weapons, but Tehran says it is civilian and peaceful.

Each year, Iran commemorates the uprising and victory of the revolution on February 11, 1979 when the army declared its neutrality. This year the anniversary falls on February 10 because it is a leap year on the Iranian calendar.

The rally will be addressed by hardline President Mahmoud Ahmadinejad, although the presence of supreme leader Ayatollah Ali Khamenei has yet to be confirmed.

"Like every year, the Iranian nation will turn out in force and this will make the enemy understand he has failed," Khamenei said on Saturday.

For the past 10 days Tehran has been festooned with flags to mark the return from exile in France on February 1, 1979 of Ayatollah Ruhollah Khomeini, founder of the Islamic republic, sparking the revolution.