Palestinian militants on Thursday evening fired a Grad rocket that struck a synagogue in the southern town of Netivot, causing light damage to the building. The Israel Air Force retaliated shortly after the attack, striking four smuggling tunnels in the southern Gaza Strip, the army said.

No one was wounded in the rocket attack on Netivot.

Earlier Thursday, an Israel Air Force strike on the Gaza Strip killed three members of the militant Islamic Jihad, according to medical sources.

In a statement issued after the strike on the tunnels, the Israel Defense Forces said: "As the sole authority in the Gaza Strip, Hamas bears full responsibility for all terror originating within its area of control. The IDF will continue to respond to any attempts to destabilize Israel's South."

Palestinian militants also launched a barrage of Qassam rockets and mortar rounds into Israel on Thursday.

They fired six Qassams from the Hamas-controlled territory into the western Negev; all struck open areas, and caused no damages or injuries. Two mortar shells struck near the Nahal Oz region, also causing no casualties.

On Wednesday night, an IAF missile attack killed a senior Islamic Jihad militant in northern Gaza and critically wounded another, Palestinian security and health officials said.

Islamic Jihad vowed revenge in the wake of the air strikes.

The IDF said the Wednesday attack targeted senior Islamic Jihad member Khaled Shalan, who had been involved in firing rockets at the southern city of Ashkelon.

Islamic Jihad, a smaller faction than Hamas, said Shalan had overseen its rocket launches and other attacks on Israel from northern Gaza.

Wednesday's strike was the second time since the end of Operation Cast Lead that the IDF has conducted targeted killings against Palestinian militants.

Palestinian security officials said the two militants jumped out of their car when they heard the IAF jet approaching. The Israeli aircraft fired a missile at them, critically wounding them. Palestinian health ministry official Moaiya Hassanain said another five bystanders were wounded.

Israel launched a 22-day military offensive in the Gaza Strip in December and has generally responded to Palestinian rocket attacks since then with air strikes on suspected smuggling tunnels on the Gaza-Egypt frontier.

Wednesday's air strike could signal a resumption of targeted killings against militant leaders.