The Israeli 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 monthlong war in 2006. The border area has remained tense but mostly quiet since then.

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 Israel brutal offensive against Palestinians in Gaza last year.

* This story was edited by Ahram Online.