Hizbullah leader Sheik Hassan Nasrallah called on members of his guerilla force to be on alert in southern Lebanon in case of an Israeli attack.
According to Nasrallah, Hizbullah was ready to confront any Israeli "aggression" against Lebanon. He did not threaten to open a war with Israel but said he feared a possible attack.
His comments came as Israel continued two days of intensive air raids against Hamas targets in the Gaza Strip.
Nasrallah spoke from a secret location through a giant screen to hundreds of supporters who gathered in the Hizbullah stronghold of Beirut's southern suburbs.