Three rockets were fired from Lebanon into Israeli territory Wednesday and the army responded with sustained artillery fire, Israel's military said.
There was no immediate information on damages or casualties.
The announcement came after sirens sounded in northern Israel warning of a possible rocket attack from Lebanon.
Two rockets landed inside Israeli territory, the army said, adding that it fired artillery back into Lebanon.
Local media reported one rocket exploded in an open area and another was intercepted by Israel's defense system, known as the Iron Dome.
A Lebanese army official said the military had no comment pending investigations.
However, several witnesses in the border area in south Lebanon said two rockets landed in an Israeli community across the border, followed by multiple artillery shells that were fired from Israel.
The Israeli shells landed in an area between the Lebanese villages of Marjayoun and Khiam, they said, adding it was not clear where the rockets were fired from.
There have been several similar incidents in recent months.
The rocket fire is believed by Israeli authorities to have been launched by Palestinian groups based in Lebanon and not the Hezbollah group.
Additional reporting by The Associated Press.