Israeli strikes on south Beirut and its suburbs killed at least four people on Sunday, a day after Israel threatened to hit Lebanon's main border crossing with Syria, forcing it to close.

President Joseph Aoun hit back Sunday at those who have criticized the Lebanese state for pursuing diplomacy and negotiations.

Hezbollah on Sunday said it had targeted an Israeli warship with a cruise missile off the Lebanese coast, the first such claim by the group since the start of the Middle East war.

The Israeli military said on Saturday it would strike the main crossing between Syria and Lebanon, urging people to evacuate immediately.

Maronite Patriarch Beshara al-Rahi on Saturday said Iran is violating Lebanon's sovereignty "through Hezbollah," in comments related to the war that has been raging since March 2.

The Israeli military said Saturday it had begun striking "Hezbollah infrastructure" in Beirut's southern suburbs after it destroyed a bridge in West Bekaa to allegedly prevent the Iran-backed group's reinforcements from crossing.

Israel destroyed a bridge in West Bekaa on Friday, Lebanese official media reported, after Israel's military warned it would hit two bridges in the area to prevent possible transfer of reinforcements to Hezbollah.

The United Nations force in Lebanon said a blast at one of its positions wounded three peacekeepers on Friday, the third such incident in a week.

The U.S. embassy in Lebanon, where Tehran-backed Hezbollah is at war with Israel, said on Friday that Iran and allied groups could seek to target universities in the country.

Fresh strikes hit Beirut's southern suburbs on Friday as the Israeli army said it was striking Hezbollah "infrastructure", hours after the Israeli army issued an evacuation warning for the area.