Iranians stormed two British Embassy compounds in Tehran Tuesday.

The incident brought to mind the seizure of the U.S. Embassy in Tehran by Iranian students on November 4, 1979. Here are details of that siege.

* Students helped spearhead the overthrow of the U.S.-backed Shah, Mohammad Reza Pahlavi, in the 1979 Islamic revolution. The Shah, who was already gravely ill, sought refuge overseas.

* Exiled cleric Ayatollah Ruhollah Khomeini returned to Iran in triumph to seal victory for a revolution whose mantra was Death to America.

* Student activists in coordination with radical clerics stormed the U.S. embassy, taking 90 hostages. Fifty-two were held captive for 444 days with the students demanding the extradition of the deposed Shah from the United States.

* The siege prompted then U.S. President Jimmy Carter to freeze Iranian assets and sever all diplomatic ties with Tehran.

* On April 25, 1980, a U.S. commando mission to rescue the hostages was abandoned in the desert with the loss of eight American lives when a helicopter collided with a tanker aircraft, politically damaging President Carter.

* Iran freed the hostages to coincide with the inauguration of Carter's rival Ronald Reagan on January 20, 1981.

* The Shah died in exile in Egypt in July 1980.

* Ayatollah Khomeini, founding father of the Islamic revolution, was reported to be initially unsure about the students' action but embraced it when he saw the crowds in front of the embassy compound voicing support for the takeover.

(Reporting by David Cutler, London Editorial Reference Unit)