At least four people were killed when an Israeli strike hit an apartment in the Ramada hotel building in central Beirut early on Sunday, with Israel saying it targeted Iranian commanders operating in the Lebanese capital.
The attack marked the first Israeli strike in the heart of Beirut since Israel-Hezbollah hostilities resumed last week, and prompted fears the scope of Israel's strikes would expand outside areas where Hezbollah has traditionally operated.
Israel said it targeted key commanders of Iran's elite Quds Force of the Revolutionary Guards but did not name them.
"The commanders of the Quds Force's Lebanon Corps operated to advance terror attacks against the state of Israel and its civilians, while operating simultaneously for the IRGC in Iran," the Israeli military said in a statement.
Lebanon was pulled into the widening US-Israel war with Iran on Monday after the Iran-backed militant group Hezbollah fired rockets and drones into Israel.
Israel responded with heavy strikes across southern and eastern Lebanon and near Beirut.
The Raouche neighborhood on Beirut's seafront is typically a tourist attraction, but in recent days has hosted an influx of displaced people fleeing strikes in southern Lebanon and Beirut's southern suburbs.
Some of those displaced had been staying at the Ramada hotel. Several were seen leaving the building for fear of further air strikes.
The strike appeared to hit a corner suite on the hotel's fourth floor. A Reuters reporter observed the windows of the suite were shattered and surrounding facade blackened.
Ten people were also injured in the attack on Beirut's Raouche area, the Lebanese health ministry said in a statement.

Khalil Abou Mohammad was staying in a building across the street after being displaced earlier this week from Beirut's southern suburbs.
His three children were wounded by the force of the strike and were receiving treatment at a nearby hospital. He showed Reuters bloodstained bed covers and said his children would need surgery.
After being displaced, “we came to stay here, and as you can see, we were sleeping at 3:30 (a.m.) and the strike hit," Abou Mohammad told Reuters.
Israel has warned any representatives of Iran in Lebanon to leave immediately or risk being targeted, and struck an area near the Iranian embassy in Lebanon earlier this week.