FACTBOX: What is Hezbollah?

(Reuters) - Hezbollah suffered a setback in Lebanon's June 7 parliamentary election, won by U.S.-backed opponents of the Iranian- and Syrian-backed Shi'ite group and its allies, but it remains a potent force.

Following is some background about Hezbollah:

HISTORY

* Hezbollah, meaning "Party of God" in Arabic, shares the Shi'ite Islamist ideology of Iran. It was set up with the help of Iranian Revolutionary Guards to fight Israeli forces that had invaded Lebanon in 1982. Hezbollah still has strong support from Tehran. It is also backed by Damascus. The United States lists Hezbollah as a terrorist organization.

* The group fought a 34-day war with Israel in 2006 that cost 1,200 lives in Lebanon and 159 in Israel. The war began with a July 12 cross-border raid in which Hezbollah seized two Israeli soldiers, whose bodies it eventually traded for Lebanese prisoners held by Israel. Despite U.N. resolutions and an expanded U.N. peacekeeping force, Hezbollah has since rearmed.

* Hezbollah, which had fought Israeli occupation forces for nearly two decades, claimed victory in 2000 when Israeli forces withdrew from mainly Shi'ite south Lebanon.

* Shadowy groups linked to Hezbollah carried out suicide attacks on Western targets in Lebanon in the 1980s and took scores of Westerners hostage -- some of whom were traded for U.S. arms shipments to Iran. Their most spectacular assault was a suicide bombing that destroyed the U.S. Marine headquarters in Beirut in October 1983, killing 241 servicemen. Another suicide bomber hit a French barracks in Beirut at the same time, killing 58 paratroopers. The attacks were claimed by the Islamic Jihad group, thought to be led by Imad Moughniyah, who was Hezbollah's military chief when he was assassinated in Syria in 2008.

HEZBOLLAH TODAY

* It is a political movement with a guerrilla army and a network of social services. It draws its support from Lebanon's Shi'ite community and is the most influential Shi'ite faction.

* Hezbollah raised its political profile in 2005 after Syrian troops left Lebanon and an anti-Syrian coalition won an election which gave Hezbollah 14 of parliament's 128 seats.

* Two Hezbollah ministers served under Prime Minister Fouad Siniora, but quit in November 2006 because the ruling coalition refused to give the opposition veto power in cabinet. Hezbollah and its allies, including the Shi'ite Amal movement and Christian leader Michel Aoun, finally won that demand in May 2008 after Hezbollah-led gunmen briefly took over Beirut. The group has one minister in the cabinet Siniora formed last year.

* Hezbollah is the most powerful military force in Lebanon, stronger than the army. It says it needs its arsenal to defend Lebanon from Israel and will only consider giving it up as part of a yet-to-be-agreed national defense strategy.

* U.N. Security Council Resolution 1559, sponsored by the United States and France and adopted in 2004, demanded that all Lebanese militias be disarmed. Hezbollah, the only one to keep its arms after the 1975-90 civil war, is defying the measure.

* Hezbollah had long sworn to use its weapons only against Israel. But it turned them on its Lebanese foes in May 2008 after its leader, Sayyed Hassan Nasrallah, said for the first time this was justified to defend the role of the "resistance."

(Editing by Alistair Lyon)