Iran is a Persian, Muslim, non-Arab state located in the predominantly Arab Middle East. It opposed the creation of the Jewish state in the United Nations General Assembly vote in November 1947 on the Palestine Partition Plan but subsequently established diplomatic relations with Israel. During the reign of Mohammed Reza Shah Pahlavi, mutually beneficial relations developed between Israel and Iran that involved, among other activities, the sale of oil to Israel and Israeli assistance with various developmental projects in Iran. Positive, if low-profile, political linkages were also established.
Following the Iranian Revolution in 1978, diplomatic relations between the two states were broken as the Islamic Republic of Iran established close formal links with the Palestine Liberation Organization. Under the Ayatollah Khomeini, Iran called for the termination of the Jewish state and the liberation of Jerusalem from Israeli control. Despite this hostile rhetoric, Israel was involved in efforts of the United States to transfer weapons to Teheran during the Iran-Iraq War of the 1980s ("Irangate") in exchange for the release of American hostages held in Lebanon by Iranian-backed forces. Hostility and vituperative rhetoric have been the hallmarks of Iran's approach to Israel since the accession of the Islamic Republic regime in Teheran. This hostility is manifested in Iran's active support for such Muslim terrorist groups as Hezbollah, Hamas, and Palestinian Islamic Jihad that commit acts of terror against Israel and against Israeli and Jewish targets internationally. Teheran also remains steadfastly opposed to the Arab-Israeli peace process and has acted to destabilize the Middle East, including acquiring or developing weapons of mass destruction and the long-range missile capability to deliver those weapons. After becoming president of Iran, Mahmoud Ahmadinejad in 2005 made a series of speeches and statements in which he raised doubts about the Holocaust and threatened the use of nonconventional weapons against Israel.
Historical Dictionary of Israel. Bernard Reich David H. Goldberg. Edited by Jon Woronoff..