Israel was wading into a devastating civil war that had been tearing Lebanon apart for eight years

By the Editorial Team · Saturday, October 17, 2026

In the summer of 1982, Israel launched a major military invasion into Lebanon, besieging Beirut and escalating the Lebanese civil war. This campaign prompted Iran to deploy Revolutionary Guard forces to the region, initiating a long-term strategic alliance with Syria and shaping ongoing hostilities involving Israel, the U.S., and Iran.

In the summer of 1982, Israel undertook a significant military campaign deeper into Lebanese territory amid an ongoing civil war that had been ravaging Lebanon since 1975. This conflict involved right-wing Christian militias opposing Palestinian fighters and their Lebanese leftist allies, with Syria seeking to extend its influence over the country. Backed by the Christian militias, the Israel Defense Forces (IDF) advanced and besieged Beirut for two months, resulting in the deaths of approximately 17,000 people during that summer alone.

The 1982 invasion marked a turning point in the region, drawing the United States further into the complex Lebanese conflict, which ultimately claimed around 150,000 lives by its conclusion in 1990. Several weeks after the initial Israeli assault, hundreds of U.S. Marines arrived in Beirut as part of an international peacekeeping mission. Meanwhile, the invasion prompted Iran to deploy fighters from its Islamic Revolutionary Guard Corps (IRGC) into Syria and Lebanon, signaling the beginning of Iran's direct military involvement aimed at countering Israeli and American presence.

This escalation laid the foundation for decades of confrontation among Israel, the United States, and Iran, with each side perceiving the struggle as existential. Over time, Iran’s influence in Lebanon and Syria strengthened, leading to the rise of proxy groups that continue to challenge Israel. Recent hostilities have included Iranian-backed Houthi missile and drone attacks targeting Saudi Arabia, alongside Israeli strikes against southern Lebanon, indicating a persistent and widening regional conflict.

Among the early Iranian fighters sent to Syria and Lebanon was a contingent of 600 men, including Ahmad Motevaselian, a battle-hardened commander from the Iran-Iraq War. These forces departed from Tehran on a repurposed Boeing 747 and arrived in Damascus in the summer of 1982. Led by Mohsen Rezaei, then a senior IRGC commander and now a senior security official in Tehran, the group was part of Iran’s broader strategy to support Syria and counter Israeli advances. Syria, under President Hafez al-Assad, sought to defend its interests after losing the Golan Heights to Israel in the 1967 Six-Day War and faced the prospect of Israeli forces moving closer to its borders via Lebanon.

Hafez al-Assad’s regime, despite ideological differences with Iran’s Islamic theocracy, aligned with Tehran in opposing Israel and the United States. The Syrian government hosted the Iranian force in disused military barracks near the Lebanese border as the fighters prepared for operations in the region. This cooperation marked the beginning of a strategic partnership that would shape the dynamics of Middle Eastern conflicts over the next several decades.

The events of 1982 remain crucial in understanding today’s regional tensions. The decisions made during that period not only intensified the Lebanese civil war but also expanded the involvement of external powers, embedding a pattern of confrontation that continues to influence interactions between Israel, Iran, and the United States.

This article was reported by synthesizing coverage from multiple independent news outlets to present a balanced, unbiased account. Read about our editorial standards. Spotted an error? Let us know.