TEHERAN - Tens of thousands of Iranians held demonstrations nationwide on Monday to mark the 40th anniversary of the seizure of the US embassy in Teheran.

In the capital city of Iran, the demonstrators gathered outside the former US embassy, calling it a "den of espionage" and carrying placards condemning US policies against Iran. They also chanted slogans against the United States and Israel and set flags of the two countries on fire.

Rallies were also reported in the cities of Mashhad, Shiraz and Isfahan, among others. The Mehr News Agency, owned by the Islamic Ideology Dissemination Organization, estimated that "millions of people" attended rallies across the country, though it was not possible to verify that claim.

State TV aired segments of a Canadian documentary, The Fire Breather, showing Donald Trump on the campaign trail in the 2016 presidential election. The segments carried biting comments about his past alongside images of the rallies that helped put him in the White House.

On Nov 4, 1979, the US embassy was stormed by Iranian students and its staff were held hostage for 444 days. The United States broke off diplomatic relations with Iran in 1980 and the ties between the two countries have since remained severed.

The 40th anniversary came at a time of escalating tensions between Teheran and Washington, and the mounting sanction pressures of Trump's administration against the Islamic republic.

New centrifuges move

Later on Monday, Iran announced its latest violations of the nuclear deal with world powers, saying that it now operates twice as many advanced centrifuges banned by the 2015 accord and is working on a prototype that's 50 times faster than those allowed by the deal, according to The Associated Press.

By starting up these advanced centrifuges, Iran further cuts into the one year that experts had estimated Teheran would need to have enough material to build a nuclear weapon - if it chose to pursue one.

The comments by Ali Akbar Salehi, the head of the Atomic Energy Organization of Iran, came ahead of an expected announcement by Teheran of the new ways it would break the accord.

Already, Iran has broken through its stockpile and enrichment limitations, trying to pressure Europe to offer it a new deal, more than a year after Trump unilaterally took the country out of the accord.

Speaking to state TV, Salehi said Teheran is now operating 60 IR-6 advanced centrifuges - twice as many as before. Such a centrifuge can produce enriched uranium 10 times as fast as the first-generation IR-1s allowed under the accord.

Agencies - Xinhua