New Delhi, June 18 -- The United States and Iran have signed an interim deal aimed at ending the war and reopening the Strait of Hormuz. However, questions remain over how further negotiations will go over the next 60 days on Iran's nuclear program.

Here's a timeline of the tensions over Iran's atomic program:

Early days

1967 - Iran takes possession of the Tehran Research Reactor supplied by America under the "Atoms for Peace" program.

1979 - U.S. ally Shah Mohammad Reza Pahlavi, fatally ill, flees Iran as popular protests against him surge. Ayatollah Ruhollah Khomeini returns to Tehran and the Islamic Revolution sweeps him to power. Students seize the U.S. Embassy in Tehran, beginning the 444-day hostage crisis. Iran's nuclear progra...