The Israeli army said that one officer was killed and two others were wounded in an air-borne raid on a Hezbollah stronghold in eastern Lebanon on Saturday.
One of the two wounded soldiers was in serious condition, said the army, adding that the other sustained light injuries.
The wounded have been evacuated to Rambam Hospital in the northern Israeli city of Haifa, the army added.
Israeli commandos carried out a raid on a Hezbollah stronghold near the Bodai village in eastern Lebanon on early Saturday.
The pan-Arab al-Jazeera satellite channel reported that three Hezbollah guerillas were also killed in the raid.
The Israeli army said that the operation was aimed to prevent weapons being transferred to Hezbollah from Iran and Syria.
It is the first Israeli raid deep inside Lebanon since a ceasefire between Israel and Hezbollah came into effect on Monday under a UN Security Council resolution.
The truce ended the 34-day-long Israel-Hezbollah conflict which was triggered by the capture of two Israeli soldiers by Hezbollah during cross-border raids on July 12.