Israeli police spokesman Micky Rosenfeld said a single rocket from Lebanon hit northeastern Israel, but caused no casualties.
In a statement, the Israeli military said it views the incident as "grave" and holds the Lebanese government responsible.
Lebanon's official news agency said unknown elements unleashed a Katyusha rocket from a valley between the Lebanese border villages of Houla and Mais al-Jabal.
About 45 minutes later, Israeli artillery shelled the area from which the rocket was fired, the agency said.
A Lebanese military official said nine shells fell on the area and Israeli helicopters and drones flew over the area.
The official spoke on condition of anonymity in line with government regulations.
There was no immediate claim of responsibility for the rocket launch.
A Hezbollah official refused to comment on the rocket firing when contacted by The Associated Press late Tuesday.
Yasmina Bouziane, a spokeswoman for the U.N. peacekeeping force known as UNIFIL deployed in southern Lebanon after the 2006 Israel-Hezbollah war, said the force "is ascertaining the facts and looking into the incident."
The Lebanon-Israel border has been largely quiet since Israel and the militant group Hezbollah fought a bitter war in the summer of 2006. That war ended with a U.N.-brokered cease-fire that saw thousands of Lebanese troops and international peacekeepers deployed to keep the peace in south Lebanon.
Hezbollah has not claimed responsibility for any attacks since the end of the fighting, which ravaged Lebanon's south.
But smaller militant organizations, some of them linked to Al Qaeda, have launched rockets on several occasions. The last one was on Sept. 11.
Tuesday's attack was the fifth this year. None have caused serious casualties.