Palestinian militants in the Gaza Strip on Wednesday launched a mortar shell at southern Israel, which exploded in the Eshkol Regional Council.

There were no casualties reported in the incident, which came a day after Gaza militants fired the first Grad rocket at Israel since the end of the Israel Defense Forces' 22-day offensive against the Hamas-ruled coastal territory.

Three people were treated for shock after the attack, which also caused damage to property.

Prime Minister Ehud Olmert and Defense Minister Ehud Barak instructed the IDF to launch reprisal attacks against Hamas targets following the Tuesday morning attack.

Olmert vowed the "smallest provocation would bring the harshest reaction" until the rocket fire on Israel ceased.

Hours later, an Israel Air Force aircraft bombed smuggling tunnels connecting Gaza with Egypt, as well as Hamas training position in the central strip. There were no casualties in those incidents.