Here’s a Timeline of Recent Strikes and Retaliations in the Middle East

Before Sunday’s attacks, tensions in the Middle East had been high for weeks in the wake of high-profile assassinations of senior leaders of the militant groups Hamas and Hezbollah.

The July killings intensified the longstanding conflict between Israel and Iran, which backs Hamas and Hezbollah and which has threatened retaliation. They also fueled alarm among global leaders, including in the United States, where the Biden administration has urged restraint to prevent a broader war from engulfing the region.

Here are some of the key developments in recent months.

Jan. 2: A Hamas leader’s killing in Beirut

Hamas accused Israel of killing Saleh al-Arouri, a senior leader, along with two commanders from its military wing in an explosion in a suburb of Beirut, Lebanon’s capital. Previously, Beirut had been far from the cross-border violence between Israel and Hezbollah, the powerful Lebanese militia that, like Hamas, is aligned with Iran. Mr. al-Arouri was the first high-level Hamas official to be killed outside the West Bank and Gaza in recent years. Israeli officials declined to comment, but Lebanese and U.S. officials attributed the attack to Israel.

Jan. 6: Hezbollah’s retaliation against Israel

In response to Mr. al-Arouri’s assassination, Hezbollah fired a volley of rockets at a small military base in northern Israel. Though Hezbollah said it caused casualties, the Israeli military reported no injuries and responded with its own strikes in Lebanon. Analysts viewed Hezbollah’s response as a symbolic act rather than a significant escalation, with the group firing about 40 rockets toward Mount Meron, an area housing a military radar station.

April 1: Airstrikes in Damascus

Israel carried out airstrikes that hit part of the Iranian Embassy complex in Damascus, Syria, killing three senior Iranian commanders and four officers involved in Iran’s covert operations. The attack, one of the deadliest in the yearslong shadow war between Israel and Iran, increased regional tensions, which were already strained over the war in Gaza and hostilities involving Iran-backed groups. Israeli officials, speaking anonymously, confirmed the strike but denied that the targeted building had diplomatic status.

April 14: A barrage of missiles and drones against Israel

Iran retaliated for the Damascus strikes by launching more than 300 drones and missiles against Israel, its first open attack on Israel from Iranian soil. The strikes, aimed at military targets, caused minor damage and injured a young girl. Israel intercepted most of the projectiles and others were shot down by U.S. and Jordanian defenses. The calibrated attack, telegraphed well in advance, demonstrated Iran’s effort to avoid mass casualties or direct war, analysts said.