Explainer-What is Hezbollah, the Lebanese group under pressure to disarm?

BEIRUT(Reuters) -The Lebanese government is expected to discuss Hezbollah's disarmament on Tuesday, facing pressure from the United States to make progress as Israel presses attacks on the Iran-backed group.

While President Joseph Aoun and Prime Minister Nawaf Salam aim to establish a state monopoly on arms, seeing this as vital to stabilising Lebanon, Hezbollah has rejected demands for its disarmament, saying such calls serve Israel.

WHAT ARE HEZBOLLAH'S ORIGINS?

Iran's Revolutionary Guards founded Hezbollah in 1982 during Lebanon's 1975-90 civil war, part of Tehran's effort to export its 1979 Islamic Revolution and fight Israeli forces that had invaded Lebanon in 1982.

HOW DID IT BECOME SO POWERFUL?

While other groups disarmed after Lebanon's civil war, Hezbollah kept its weapons to fight Israeli forces occupying the predominantly Shi'ite Muslim south. It kept its weapons after Israel withdrew in 2000.

In 2006, during a five-week war, it fired thousands of rockets into Israel. The war erupted after Hezbollah crossed into Israel, kidnapping two soldiers and killing others.

Hezbollah's arsenal grew after 2006. The U.S. Central Intelligence Agency's World Factbook said it was estimated to have as many as 150,000 rockets and missiles in 2020 and in 2022 was estimated to have 45,000 fighters.

Hezbollah's veteran leader Hassan Nasrallah, killed by Israel in 2024, said the group had 100,000 fighters. 

HOW DID IT GET INVOLVED IN THE GAZA WAR?

After the 2006 war, Hezbollah became involved in conflicts outside Lebanon. It sent fighters to Syria to help Bashar al-Assad fight rebels, aided Iran-backed Shi'ite militias in Iraq, and supported the Houthis of Yemen, sending fighters to assist them in their war with a Saudi-led coalition, according to Riyadh, though Hezbollah has never confirmed this.

It also deepened ties with Palestinian militant group Hamas. Hezbollah became the spearhead of the Iran-backed "Axis of Resistance".

After Hamas attacked Israel on October 7, 2023, Hezbollah opened fire on Israeli positions in the frontier region, declaring solidarity with the Palestinians.

Hezbollah and Israel traded fire for almost a year until September 2024, when Israel detonated thousands of booby-trapped pagers used by Hezbollah members, and stepped up airstrikes, killing Nasrallah and other commanders. 

Israel also sent troops into Lebanon's south.

HOW BADLY HIT WAS HEZBOLLAH?

In addition to killing much of Hezbollah's command, Israel killed thousands of fighters and destroyed much of its arsenal.

The toppling of Assad in Syria in December 2024, choked Hezbollah's main supply route from Iran and tilted the regional power balance against it.

A U.S.-backed ceasefire agreed in November 2024 required Hezbollah's disarmament beginning in areas south of the Litani River, the area adjacent to Israel. 

Hezbollah says the deal only applies to that region and that it has handed over weapons to Lebanese troops in that area. Israeli forces continue to occupy five hilltops in the south and to carry out airstrikes on Hezbollah fighters and arms depots.

WHAT IS HEZBOLLAH'S ROLE IN LEBANON?

Hezbollah long had a decisive say over state affairs but was unable to get its way over the formation of the 2025 post-war government, which adopted a policy of establishing a monopoly on arms.

Lebanese have been at odds over Hezbollah's arms for decades - opponents accuse it of dragging Lebanon into wars, supporters see its weapons as key to defending the country.

In 2008, Hezbollah fighters took over parts of Beirut in an armed conflict sparked by the government's vow to take action against the group's military communications network.

A U.N.-backed court convicted three Hezbollah members in absentia over the assassination of former prime minister Rafik al-Hariri, a Sunni Muslim politician killed in 2005 by a truck bomb in Beirut, along with 21 other people. Hezbollah has denied any role.

Hezbollah has solid backing among Shi'ites. The group has been represented in governments, either by Hezbollah politicians serving as ministers or through its approval of candidates for cabinet portfolios reserved for Shi'ites.

It runs its own social services. Together with its ally, Amal, it dominated local elections in May in Shi'ite areas. The groups hold all seats reserved for Shi'ites in parliament.

TERRORISM DESIGNATIONS

The United States holds Hezbollah responsible for suicide bombings in 1983 that destroyed the U.S. Marine headquarters in Beirut, killing 241 service personnel, and a French barracks, killing 58 French paratroopers. It also blames Hezbollah for a suicide attack on the U.S. Embassy in Beirut in 1983. 

Lebanese officials and Western intelligence agencies have said groups linked to Hezbollah kidnapped Westerners in Lebanon in the 1980s. Referring to those attacks and hostage-taking, Nasrallah said in a 2022 interview they were carried out by small groups not linked to Hezbollah.

Western governments, including the United States, and Gulf Arab states, including Saudi Arabia, deem Hezbollah a terrorist group. Some, notably the European Union, have designated its military wing a terrorist group, drawing what critics say is an artificial distinction with its political wing. 

Argentina blames Hezbollah and Iran for the bombing of a Jewish community centre in Buenos Aires in which 85 people died in 1994 and for an attack on the Israeli Embassy in Buenos Aires in 1992 that killed 29 people. Hezbollah and Iran deny any responsibility.

(Writing by Tom Perry; Editing by Janet Lawrence)