The Israeli army said "two rockets were fired from Lebanon into Israeli territory," with one intercepted by air defences while the other struck open ground.

"In response, a short while ago (Israeli) artillery struck in Lebanese territory," the army said.

A Lebanese security source told AFP the rockets were fired at Israel from the Qlaileh area of southern Lebanon, where a third rocket was also found.

The source said the Lebanese army had not identified the group responsible for the launch.

The UN peacekeeping force in the border region, UNIFIL, said it had boosted security in the area and "launched an investigation" in collaboration with the Lebanese military.

"UNIFIL is in direct contact with the parties to urge maximum restraint and avoid further escalation," it said in a statement.

The last time rockets were fired from Lebanon into Israel was in May, during an 11-day conflict between Israel and Palestinian armed groups in the Gaza Strip.

In recent weeks, Israeli security officials have expressed growing concern over the deepening economic crisis in Lebanon and its ramifications for border security.

Defence Minister Benny Gantz tweeted: "The state of Lebanon is responsible for the rockets fired overnight, as it allows terrorists to operate within its territory.

"We will not allow the social, political and economic crisis in Lebanon to turn into a security threat to Israel. I call on the international community to take action to restore stability in Lebanon," Gantz said.

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