Jerusalem: The Israeli military said it struck Lebanon with artillery fire early Monday after a rocket was fired into Israel.
The army said the rocket landed in an open area in northern Israel, causing no damage or injuries.
But shortly after, it said it struck the sources of the projectile launched and an infrastructure target in southern Lebanon.
It said routine activity in northern Israel was continuing.
There was no immediate claim of responsibility.
Israel and Lebanon’s militant Hezbollah group are bitter enemies that fought an inconclusive month-long war in 2006.
The border area has remained tense but mostly quiet since then.
Small Palestinian groups are also active in Lebanon and have been suspected in several rocket attacks in recent years.
The rocket fire came at a time of heightened tensions in Israel following a string of deadly attacks inside Israel, arrest raids in the occupied West Bank and rocket attacks into Israel launched from the Hamas-controlled Gaza Strip.
It has been the worst violence to shake the region since an 11-day war between Israel and Gaza militants last year.