The IDF said another soldier was killed and three more soldiers were wounded, including two officers, in separate incidents across southern Lebanon on Thursday.
Sgt First Class Gai Ben-Haroosh, 23, who served in a canine unit, was killed fighting Hezbollah militants, it said.
An officer from the Seventh Armoured Brigade’s 77th Battalion, was seriously hurt in an anti-tank guided missile attack, while another, from the 226th Paratroopers Brigade, was injured by shrapnel.
Another reservist, from the 55th Paratroopers Brigade, was wounded in a battle with Hezbollah fighters, the IDF said.
A total of 21 Israeli soldiers have been killed in southern Lebanon since Israel began its ground operation there around three weeks ago, Israeli media said.
On Thursday, the IDF said it had seized 3,200 explosive devices and 2,500 anti-tank missiles and rocket-propelled grenades since then.