Hezbollah is an Iran-backed Islamist movement with one of the most powerful paramilitary forces in the Middle East. The group's main base is on the Israeli-Lebanese border, where the effects of the war between Israel and Hamas are being felt. Hezbollah and Israel have been skirmishing since the war began, putting the entire region in a bind and raising fears that this could spark a larger regional conflict.

This is the latest incident in a decades-long conflict between Hezbollah and Israel. Here's what you should know:

Israeli Invasion: In the 1982 invasion of Lebanon, Israeli forces captured almost half of Lebanon's territory, including Beirut, where Israeli forces joined right-wing Christian Lebanese militias allied with Israel in laying siege to the western part of the capital to drive out Palestinian militants.

According to contemporary reports and an Israeli investigation into a massacre in Beirut's Sabra and Shatila refugee camp, Israel's operation resulted in more than 17,000 deaths, one of the bloodiest events in the region's recent history. The investigation, known as the Kahan Commission of Inquiry, indirectly blamed Israel for the massacre, which was carried out by right-wing Christian Lebanese fighters. Estimates of the death toll in Sabra and Shatila vary from 700 to 3,000.

The rise of Hezbollah: As hordes of Palestinian fighters left Lebanon, a group of Shiite Islamist fighters trained by the nascent Islamic Republic of Iran burst into Lebanon's fractious political landscape. The ragtag group had enormous and violent influence. In 1983, two suicide bombers linked to the faction attacked a U.S. Marine barracks in Beirut, killing nearly 300 American and French soldiers and some civilians.

A year later, Iranian-linked fighters bombed the U.S. embassy in Beirut, killing 23 people. In 1985, these militants more formally merged into a newly formed organization: Hezbollah.

A “supporting front” for Gaza in 2023: Hezbollah is part of a larger Iran-led alliance of militant groups in Yemen, Syria, Gaza and Iraq that has been increasingly involved in clashes with Israel and its allies since the war with Hamas began on October 7, 2023. The alliance has said it will continue to attack Israeli targets as long as the war in Gaza continues, describing itself as a “supportive front” for Palestinians in Gaza, as one senior Hezbollah leader described it.

Killing an important leader: After months of sparring, tensions escalated when Israel said it had killed Hezbollah's top military commander, Fu'ad Shukr, in a July attack on Beirut. In retaliation, Hezbollah fired hundreds of drones and missiles at targets in Israel in August. Israel denied that any major targets were hit, and no evidence has been released to refute this denial.

Displaced residents: The increase in cross-border fighting has displaced people from their homes in both northern Israel and southern Lebanon. Israel has made it a new war goal to return tens of thousands of northern Israeli residents to their homes near the border. Officials and residents of the northern region are increasingly putting pressure on the Israeli government about the need for return. According to the Lebanese Health Ministry, over 100,000 people have been displaced from southern Lebanon.

Latest attack: Hezbollah confirmed that senior commander Ibrahim Aqil was killed. Israel said Aqil was one of the senior Hezbollah figures killed in an airstrike on a Beirut apartment building. Lebanon was already reeling after thousands of small explosions hit Hezbollah members' pagers and walkie-talkies over the course of the week, killing dozens and wounding thousands.