Thousands of Iranians have attended a major anti-US rally marking the anniversary of the 1979 takeover of the US Embassy in Tehran.
The gathering outside the former embassy compound came days before a key meeting between the two nations' senior diplomats over Iran's controversial nuclear programme.
The crowds chanted "Down with America" as well as "Death to Israel" and "Death to Britain", neither of which has an embassy in Tehran. Several protesters burned US, Israeli and UK flags.
The protest was smaller then last year's event which drew tens of thousands - a sign of improved Iran-US relations since moderate Iranian president Hassan Rouhani took office last year.
But the rally, organised by hardliners, still puts pressure on Mr Rouhani, whose policy of outreach to Washington has faced harsh criticism from opponents at home.
After the Islamic Revolution in Iran 35 years ago, militant Iranian students stormed the US Embassy, claiming it was a centre of plots against the nation, and held 52 Americans hostage for 444 days. Ties between the two countries were severed after the siege and formal relations have not been restored.
The anti-US gathering this year also had a religious character as most Shiites around the world observed the Ashoura, a remembrance of the 7th-century death of Imam Hussein, a grandson of the Prophet Mohammed revered by Shiites.
One of the rally speakers, cleric and university professor Ali Reza Panahian, compared the US to enemies Imam Hussein faced in his final battle in Karbala in present-day Iraq.
"Today, the evil, arrogant powers have learned that they should not attempt to thwart us in the same way that enemies of Hussein encircled him," Mr Panahian said. He also denounced talks with world powers over Iran's nuclear programme, claiming the negotiations cannot change the Iranians' anti-US stance.
State TV said similar anti-US rallies took place in other Iranian cities and towns.
Despite anti-American sentiment on the streets, Mr Rouhani's government has pushed for a final nuclear deal that would end crippling Western sanctions imposed on Iran in exchange for ensuring that Tehran cannot produce a nuclear weapon.
The two sides have a November 24 deadline to seal a final deal. The West suspects Iran's nuclear programme is aimed at producing atomic weapons, a charge Tehran denies, insisting it is for peaceful purposes only.
Supreme leader Ayatollah Ali Khamenei, who has final say on all Iranian state matters, has repeatedly backed the talks even though he has expressed doubts about the intentions of the six-member negotiating group - the five permanent UN Security Council members - the US, UK, China, France and Russia - plus Germany.
US secretary of state John Kerry and his Iranian counterpart Mohammad Javad Zarif are to hold talks in Oman next week, which will also include the European Union's foreign policy chief Catherine Ashton.
Mr Zarif's adviser Ali Khorram said Iranian-US relations have changed from being openly hostile to friendly, but that "it's a friendly relation not based on trust, not yet".
Mr Khorram said the two have "common fields of co-operation in Iraq and Syria" against Islamic State extremists.