JERUSALEM: Israeli tanks fired into southern Lebanon early on Monday in response to a rocket fired from the country, the Israeli military said.
The incident along Israel's northern border comes at a time of heightened tensions between Israelis and Palestinians.
Recent weeks have seen a string of deadly attacks inside Israel, lethal arrest raids by Israel in the occupied West Bank and rocket attacks into Israel launched from the Hamas-controlled Gaza Strip, as well as clashes in a key Jerusalem holy site.
It has been the worst violence to shake the region since an 11-day war between Israel and Gaza militants last year.
In a statement, the Israeli military said the rocket landed in an open area in northern Israel early Monday, causing no damage or injuries.
Shortly after, the military 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 and there were no special precautions being asked of civilians in the area.
There was no immediate claim of responsibility for the rocket fire, but Brig.
Gen.Ran Kochav, the military spokesman, told Israeli Army Radio that he assumed the rocket was launched by Palestinian militants in Lebanon spurred on by the recent events in Israel, the West Bank and Gaza.
He said Israel's response was meant to make clear to all who are on the other side, whether it is Palestinian factions, Hamas, the government of Lebanon or Hezbollah that we won't allow Israeli sovereignty to be violated, he said.
Lebanon's military said at least 50 artillery shells struck several areas in the south early Monday but reported no casualties or damages.
It said Israel also launched 40 flare bombs.
The military also said special Lebanese units dismantled two 122-mm Grad rocket systems found in the southern town of al-Qulailah.
Israel and Lebanon's militant Hezbollah group are bitter enemies that fought an inconclusive monthlong 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.