From the CIA-orchestrated overthrow of Iran's prime minister in 1953 to Friday's phone call between Presidents Obama and Rouhani, BBC News looks at 60 years of tricky relations between Iran and the US.
1953: Overthrow of Mossadeq
US and British intelligence agencies orchestrate a coup to oust Iran's democratically elected Prime Minister, Mohammad Mossadeq. The secular leader had sought to nationalise Iran's oil industry.
The US-backed Shah of Iran, Mohammed Reza Pahlevi, is forced to leave the country on 16 January following months of demonstrations and strikes against his rule by secular and religious opponents.
Two weeks later, Islamic religious leader Ayatollah Khomeini returns from exile. Following a referendum, the Islamic Republic of Iran is proclaimed on 1 April.
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From the moment the hostages were seized until they were released minutes after Ronald Reagan took the oath of office as president 444 days later, the crisis absorbed more concentrated effort by American officials and had more extensive coverage on television and in the press than any other event since World War II
Historian Gaddis SmithIn November 1979 Iranian students overrun the US embassy in Tehran, seizing 63 hostages and parading them in front of the cameras. Their initial demand is for the Shah to return to face trial in Iran.
A rescue mission ends in disaster for US troops, with the deaths of eight servicemen in a collision between a helicopter and a transport plane.
The final 52 hostages are eventually freed after 444 days in captivity.
Mohammad Khatami, a reformist, is elected Iranian president in 1997.
The following year he calls for "a dialogue with the American people" in an interview with a US TV channel. The prospect of a thawing in relations beckons, but there is no breakthrough.
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Iran aggressively pursues weapons [of mass destruction] and exports terror, while an unelected few repress the Iranian people's hope for freedom
President George W. BushAddressing CongressIn his State of the Union address, President George Bush denounces Iran as part of an "axis of evil" with Iraq and North Korea.
In 2002 an Iranian opposition group reveals that Iran is developing nuclear facilities including a uranium enrichment plant at Natanz and a heavy water reactor at Arak.
The US accuses Iran of a clandestine nuclear weapons programme, which Iran denies.
A decade of intermittent Iranian engagement with the UN's nuclear watchdog and diplomatic activity follows.
The UN ratifies four rounds of sanctions on Iran between 2006 and 2010 over the nuclear issue.
The US and EU also impose sanctions on Iran, stepping up measures in 2012 to include the financial sector. Several other countries have bilateral sanctions.
The US Treasury claims in 2013 Iran's currency has lost two-thirds of its value in the past two years.
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In phone convo, President #Rouhani and President @BarackObama expressed their mutual political #will to rapidly solve the #nuclear issue.
Hassan Rouhani@HassanRouhaniOn a trip to the UN forum in New York, Iran's new President Hassan Rouhani held a phone call with President Barack Obama - the first conversation between US and Iranian heads of state for 30 years.
Mr Rouhani used his Twitter account to break the news of the historic conversation.
The US president also said the two men had expressed their determination to solve the long-running dispute over Iran's nuclear programme.