Israeli Defence Minister Israel Katz warned Lebanon's Hezbollah to exercise caution on Friday, saying Israel's patience with "terrorists" who threaten it had worn thin.
The head of Iran-backed Hezbollah, Naim Qassem, said on Thursday that the Lebanese group would act as it saw fit in the face of what he called "brutal Israeli-American aggression" against Iran.
In other statements, the group has made no explicit pledge to join the fighting and a Hezbollah official told Reuters last week that the group did not intend to initiate attacks against Israel.