A fifth Iron Dome air defence system Israeli Army ready to be used after last rockets fire 0404134.

The news came hours after a rocket fired by Palestinian militants exploded in southern Israeli town of Sderot on Wednesday morning, followed by another three projectiles that fell in open areas in the vicinity, causing no injuries or damage.

On Tuesday night, Israeli aircraft struck targets in northern Gaza Strip in retaliation for mortar shells fired at western Negev earlier in the day.

In a first official response to the latest violence, Israeli military chief Lt. Gen. Benny Gantz vowed late Wednesday that Israel will not allow the renewal of incessant rocket fire from the coastal territory.

"We will not return to the reality that existed five months ago, prior to the cease-fire," Army Radio quoted Gantz as saying.

Defense Minister Moshe Ya'alon, in remarks published earlier in the day, said Israel holds Islamist group Hamas accountable for all attacks emanating from Gaza, though Magles Shoura al- Mujahadeen, a group reportedly linked to al-Qaeda, claimed responsibility for Tuesday's rocket attack.

"We won't allow firing of any sort on our citizens and forces," Ya'alon said.