Two rockets fired from Lebanon struck northern Israel on Sunday, causing no injuries or damage, and Israel's military responded with artillery fire across the border, officials said.
The Lebanese rockets landed near the town of Kiryat Shmona, the military said in a statement, adding that it "responded with artillery fire towards the source of the launch".
A Reuters witness in the Lebanon frontier area said more than 20 Israeli shells hit near two southern border towns.
The Israeli-Lebanese border has been largely quiet since Israel and the Lebanese Hezbollah militia fought a 34-day war in 2006.
But tension spiked this month when a Lebanese soldier killed an Israeli soldier across the border fence, after which a U.N. peacekeeping force met both sides to restore calm.
Officials suggested at the time that the shooting had been the isolated action of an individual.