Israel warned that it will respond to those who fired rockets on Thursday towards its territory from the southern Lebanon.
The army said none of them hit Israeli territory, but one was shot down by the Iron Dome defence system.
Sirens sounded across northern Israel, but no casualties were reported.
The BBC reports rockets have been fired into Israel intermittently since the Israel-Hezbollah conflict in 2006.
But an Israeli army spokesman told the BBC he did not believe Hizbollah was behind the attack.
Lebanese news agencies reported all four rockets were fired from the Tyre region in southern Lebanon.
Prime Minister Benjamin Netanyahu responded swiftly:
"Whoever tries to harm us should know we will harm them," he said.
