Israel killed a top Hezbollah commander in an airstrike on Beirut's southern suburbs on Friday, the Israeli military and security sources in Lebanon said, escalating a year-long conflict between Israel and the Iran-backed group.

Hezbollah has pounded northern Israel with 140 rockets, a day after the militant group’s leader vowed to retaliate against Israel for a mass bombing attack, the Israeli military and the militant group said.

Daily exchanges of fire between Hezbollah and Israel have been destructive, disruptive and sometimes deadly. An escalation could risk starting a wider regional conflict.