A targeted Israeli strike killed a commander of Hezbollah's elite Radwan force on Monday in one of the most high-profile attacks in three months of hostilities.
More than 130 of Iran-backed Hezbollah fighters including members of the Radwan force have been killed in skirmishes across the Israeli-Lebanese border since Hamas attacked Israel from Gaza on October 7, igniting a conflict that has rippled around the region.
Wissam al-Tawil, the deputy head of a Radwan unit, and another Hezbollah fighter were killed when the car they were in was struck some 6 km (3.7 miles) from the border. There was no immediate comment from Israel.
Tawil was one of the most senior Hezbollah commanders killed in the hostilities so far.
The group circulated photographs of Tawil with Hezbollah leaders including Secretary General Sayyed Hassan Nasrallah and Imad Mughniyeh, the group's military commander who was killed in Syria in 2008.
Another photo showed him sitting next to the late leader of the Iranian Quds Force, Qassem Soleimani, who killed by a US drone strike in Baghdad four years ago.
One security source called Tawil's death "a very painful strike" in comments to Reuters. Another said, "things will flare up now."
Hezbollah says its campaign aims to support Palestinians in the Gaza Strip. The hostilities between the group and Israel have largely been contained to areas near the border.
Tensions spiked higher last week when an Israeli strike killed deputy Hamas chief Saleh al-Arouri in Beirut's southern suburbs controlled by Hezbollah.
Hezbollah's secretary-general Sayyed Hassan Nasrallah warned Israel last week not to launch a full-scale war on Lebanon.
"Whoever thinks of war with us - in one word, he will regret it," Nasrallah said.