Chanting "Death to America" and burning the US flag, Iranian protesters Wednesday marked the anniversary of the US embassy seizure with a show of anti-Washington fervour despite the nuclear deal.
The protest by thousands of Iranians follows the landmark nuclear deal sealed on July 14 by Tehran and world powers led by the United States.
The 1979 storming of the embassy in Tehran by students, months after the Islamic revolution, led to a 444-day hostage crisis and a break in diplomatic relations that continues to this day.
Demonstrators gathered outside the former embassy and across Iran for what was declared the "National Day of the Fight Against Global Arrogance" -- a term often used by supreme leader Ayatollah Ali Khamenei.
Protesters held placards with slogans including "Down with USA" and "Down with Israel".
Prosecutor General Ebrahim Raisi gave a fiery speech attacking US "atrocities" ranging from slavery and the treatment of Native Americans to phone tapping and "the killing of 300,000 Iraqis".
"A day will come when they will have to answer in court for their atrocities," he said.
On Monday, a majority of Iranian legislators said the Islamic republic would not drop the "Death to America" slogan despite the nuclear accord.
"The martyr-nurturing nation of Iran is not at all prepared to abandon the slogan of 'Death to America' under the pretext of a nuclear agreement," they said.
The legislators said the slogan, chanted at weekly Friday prayers in mosques and at protests, had "turned into the symbol of the Islamic republic and all struggling nations".
Khamenei has endorsed the nuclear deal, which curbs Iran's atomic drive in return for a lifting of sanctions, but has repeatedly warned against US "infiltration" of the values of Iranian society.
In a sign that sudden change is not on the cards, Iranian police swooped in to shutter a fried chicken shop using the brand name of US fast food giant KFC, local media reported Tuesday.
"Police closed the 'KFC' restaurant as it didn't have authorisation and had been operating under a false license," reported the news site of Iran's Young Journalist Club, which is affiliated with state television.
The fast food joint, KFC Halal, had only been open for three days, the site said.
The rapprochement has seen US fast food chains such as McDonald's and KFC reportedly explore the possibility of opening branches in Iran, something that has stirred debate among conservative Iranians.
On a more ominous note, Iran has arrested a Lebanese-American man suspected of links to the US intelligence community, state television reported Tuesday, although an official in Washington said he was a US resident but not a national.
It was unclear when or where the suspect had been arrested but the report identified him as Nezar Zaka and said he was suspected of "multiple close ties to the US military and intelligence communities."
The broadcaster aired photographs of what it said was Zaka in military uniform on a US base.
The US State Department, while not officially confirming there had been an arrest, said the suspect was Lebanese with permanent US residency papers.
Four Iranian-Americans are being held in Iran. They include Washington Post correspondent Jason Rezaian, who has been held since July last year on spy charges.
His employer says he has been found guilty in an "outrageous injustice".