The hostility between Iran and Israel, and between Iran and most Western nations generally, dates from the revolution that brought in the present Islamic republic more than three decades ago.

- 1948: Creation of the state of Israel. Iran emerged from World War II under the rule of the Western-backed Shah Reza Pahlavi.

- 1953-1979: During the heyday of the shah, who runs Iran as a police state, Israel enjoys close diplomatic and trade relations with Tehran. The latter provides some 40 percent of Israel's crude oil and imports Israeli weapons, technology and farm produce.

- 1979: The Islamic revolution led by Ayatollah Ruhollah Khomeini sends the Shah into exile and leads to the creation of an Islamic republic. Diplomatic relations with Israel and the United States are severed.

Although informal trade relations continue, the Islamic regime considers Israel an illegal occupier of Jerusalem -- a city that is holy for Muslims, Jews and Christians alike -- and describes it as the "enemy."

The advent of the new Iranian regime gives a boost to groups hostile to Israel, including the Islamic Jihad, which is to become influential among Palestinians and also in Lebanon.

Many but not all of Iran's Jewish citizens -- the largest such population in the region outside Israel -- leave after the Islamic revolution.

- 1980-88: Iran embroiled in a war with Iraq, then under the dictatorship of Saddam Hussein.
Although the Western powers generally tilt towards the Iraqis, it is later revealed that the United States has secretly supplied Iran with arms and used the money to fund counter-revolutionaries in Nicaragua.

As part of the deal, which becomes known as the "Iran-Contra scandal," Israel provides some 1,500 missiles to Iran.

- 1982: At the height of the Lebanese civil war Israel invades Lebanon, citing the need to halt Palestinian attacks on its territory from there.

The Israeli occupation heightens Iran's involvement in Lebanon. Iran's Guardians of the Revolution pay a key role in setting up the Lebanese Hezbollah organisation, which in 2000 will secure the departure of the last Israeli troops from the border zone.

- 1992 and 1994: Israel blames Iran for deadly bombings aimed at Jewish targets in the Argentinian capital Buenos Aires. Investigations into the attacks are still ongoing.

- 2000: Along with major Western countries, Israel says it suspects Iran of using a civilian nuclear programme to secretly develop atomic weapons. Israel itself is widely believed to possess such weapons.

- 2005: Mahmoud Ahmadinejad elected president of Iran. He quickly gets into the habit of making hostile statements about Israel. One comment is widely translated into English as meaning that the Jewish state should be "wiped off the map."

- 2010-present: Western powers increasingly hint that military means could be used against Iran's nuclear programme, most of which is housed in deep underground bunkers. Israel is widely reported to be preparing such an attack.
Over the same period several leading Iranian nuclear scientists are murdered inside the country.