Two militants on a motorbike killed a Lebanese Army Sergeant-Major Sunday night in the northeastern border town of Arsal, state media reported.
Sergeant-Major Khaled Ezzedine was killed immediately after the two gunmen opened fire at him at 11:30 p.m., the National News Agency said.
The soldier's body was moved to Al-Rahme Hospital.
The circumstances of the incident remain unclear.
Hundreds of militants belonging to Daesh and Jabhat Fatah Al-Sham are holed up on Arsal's outskirts.
Lebanese troops frequently launch preemptive strikes against the militant groups to keep them at bay.
The town was briefly overrun by extremists in August 2014, when the two extremist groups captured a number of Lebanese soldiers and policemen, in the worst spillover of the Syrian war to date.
It is believed that nine soldiers are still being held captive by Daesh.