In the early 1970s, tension along the Israel-Lebanon border increased, especially after the relocation of Palestinian armed elements from Jordan to Lebanon. Palestinian commando operations against Israel and Israeli reprisals against Palestinian bases in Lebanon intensified. On 11 March 1978, a commando attack in Israel resulted in many dead and wounded among the Israeli population. The Palestine Liberation Organization (PLO) claimed responsibility for that raid. In response, Israeli forces invaded Lebanon on the night of 14/15 March, and in a few days occupied the entire southern part of the country except for the city of Tyre and its surrounding area.