What is Hezbollah and why is Israel attacking Lebanon?
The Israeli military says its troops have entered Lebanon for what it calls a "limited, localised and targeted" ground operation against the armed group Hezbollah.
Lebanese officials say more than 1,000 people have been killed following Israeli air strikes over the past two weeks. Hezbollah has responded by firing hundreds of rockets into northern Israel.
What is Hezbollah and has it fought Israel before?
Hezbollah is an influential Shia Muslim political party and armed group.
It has a significant presence in both the Lebanese parliament and government, and controls the most powerful armed force in the country.
Hezbollah rose to prominence in the 1980s in opposition to Israel, whose forces had occupied southern Lebanon during the country's 1975-1990 civil war.
It has received strong backing from Iran, both financially and militarily, for many years. It is also a strong ally of the Syrian president Bashar al-Assad.
Hezbollah's armed wing has carried out deadly attacks on Israeli and US forces in Lebanon.
When Israeli troops withdrew from Lebanon in 2000, Hezbollah took credit for pushing them out and continues to oppose Israel's presence in disputed border areas.
In 2006, a full-blown war broke out between Hezbollah and Israel, triggered by a deadly cross-border raid by Hezbollah.
Israeli troops invaded southern Lebanon to try to eliminate the threat from Hezbollah. About 1,000 civilians were killed during the conflict, but Hezbollah claimed victory and has since increased its number of fighters and upgraded its weapons.
The group is designated as a terrorist organisation by Western states, Israel and Gulf Arab states.
How much political support does Hezbollah have?
Hezbollah has participated in Lebanon's national elections since 1992 and has become a major political power.
The group and its allies lost their majority in parliament in the 2022 election, but a new government has not been formed since then and it continues to have ministers in the caretaker administration.
Lebanon is deeply divided over Hezbollah. While the group enjoys substantial popular support, many opponents accuse it of involvement in political corruption and oppose its military capabilities, viewing them as a significant factor in the country's conflicts.
As a powerful political entity, Hezbollah also operates schools, hospitals, cultural institutions and charities across Lebanon.
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How strong are Hezbollah's forces?
Hezbollah has thousands of fighters and a huge missile arsenal in southern Lebanon.
It is one of the most heavily armed non-state military forces in the world. It is funded and equipped by Iran.
The organisation has claimed it has 100,000 fighters, although independent estimates put the number between 20,000 and 50,000.
Many are well-trained and battle-hardened, and have fought in the Syrian civil war.
Hezbollah has an estimated 120,000-200,000 rockets and missiles, according to the Center for Strategic and International Studies think tank.
Most of its arsenal is made up of small, unguided, surface-to-surface artillery rockets.
But it also thought to have anti-aircraft and anti-ship missiles, as well as guided missiles capable of striking deep inside Israel.
It has much more sophisticated weapons at its disposal than Hamas does in Gaza.
Who was Hezbollah leader Hassan Nasrallah?
Hezbollah had been led since 1992 by Hassan Nasrallah, a Shia cleric.
On 28 September, Israel said it had killed Nasrallah in an air strike on Beirut. Hezbollah later confirmed the death of the 64-year-old.
Nasrallah had played a key role in turning Hezbollah into a political force, as well as a military one.
He had close links with Iran and its Supreme Leader, Ayatollah Ali Khamenei.
It is unclear who will lead Hezbollah in future.
How has the conflict between Hezbollah and Israel escalated?
Israel has gone on the offensive after almost a year of cross-border hostilities sparked by the war in Gaza.
Previously sporadic fighting escalated on 8 October 2023, the day after the unprecedented attack on Israel by Hamas gunmen.
Hezbollah has since launched more than 8,000 rockets at northern Israel and the Israeli-occupied Golan Heights. It has also fired anti-tank missiles at armoured vehicles and attacked military targets with explosive drones.
The Israel Defense Forces (IDF) retaliated with air strikes and tank and artillery fire against Hezbollah positions in Lebanon.
On 17 September, Israel it wanted to ensure the safe return of residents of border areas who have been displaced by Hezbollah attacks.
It killed more than a dozen top Hezbollah commanders and apparently destroyed thousands of weapons in air strikes.
It was also blamed for the exploding pager and walkie-talkie attacks that left thousands of Hezbollah members maimed, blinded or killed.
Although Hezbollah has been weakened, it has continued to fire barrages of rockets into northern Israel and is still believed to possess a formidable arsenal of long-range missiles.