In Iran’s pantheon of hated western symbols Hollywood is already firmly established as a place of cultural decadence.

But now the country’s Islamic leadership has accused it of “psychological warfare” in its depiction of the battle between the Greeks and Persians at Thermopylae in 480BC, regarded by some as a key event in the birth of western democracy.

President Ahmadinejad’s spokesman branded the film ‘an insult to Iran’. Photograph: Warner Bros

President Mahmoud Ahmadinejad’s government has joined MPs, bloggers and local media in denouncing the newly released Warner Brothers film, 300, as a calculated attempt to demonise Iran at a time of intensifying US pressure.

Mr Ahmadinejad’s spokesman branded the film “an insult to Iran” while four MPs have urged the foreign ministry to pressure other Muslim countries to ban it.

The film, directed by Zack Snyder and based on a novel by Frank Miller, grossed nearly £40m in its first three days in North America last week. It portrays the heroic endeavours of 300 Spartans, under King Leonidas, who resist an invading force of 120,000 Persians led by Emperor Xerxes.

The tiny Spartan force is defeated only by treachery after a three-day stand-off. Iranians have complained that the film represents them as savage, murderous and warmongering.

The film is only available in Iran on pirated DVDs. But that has not stopped an outpouring of official condemnation.

The government spokesman, Gholamhossein Elham, told reporters: “Such a fabrication of culture and insult to people is not acceptable by any nation or government.

[Iran] considers it as hostile behaviour which is the result of cultural and psychological warfare.”