Israeli fighter jets struck dozens of sites across the Gaza Strip early on Saturday as fighters fired about 30 rockets into Israel, in the heaviest exchange of fire in several weeks

The fighting followed a bloody day of border protests, in which Israeli forces shot and killed five Palestinians protesting along the perimeter fence dividing Hamas-ruled Gaza and Israel

The fighting and bloodshed complicated the mission of Egyptian mediators, who have intensified shuttle diplomacy to achieve calm and prevent a full-blown conflict between the Palestinian resistance and Israeli occupation

The Israeli occupation said it had struck about 80 sites across Gaza by early Saturday morning, including a security headquarters building

There was no word on injuries as a result of the air attacks

Islamic Jihad, a smaller group, implicitly claimed responsibility for the rocket fire. It issued a statement saying that it normally exercises restraint, but it can no longer stand idle before the continued killing of innocents and bloodshed by the Israeli occupation

It was not immediately clear whether Islamic Jihad, which sometimes acts independently of Hamas, had coordinated the rocket fire with Hamas. But Israel holds Hamas

The sides have fought three wars over the past decade, and Israel and Egypt have maintained a stifling blockade on the territory. The weekly protests along the Israeli border have been aimed in large part at breaking the blockade, which has devastated the Gaza economy

On Friday, thousands of Palestinians gathered at five locations along the boundary, burning tires and throwing stones at Israeli troops who responded with live fire and tear gas

Three of the dead were reported in Khan Younis, in southern Gaza, according to the Gaza Health Ministry. Witnesses said that dozens of protesters approached the fence there

In northern Gaza, a 27-year-old man died after being shot in the head, the ministry said. It added that 170 other protesters sustained various injuries

On Wednesday, Egyptian intelligence officials met representatives of Palestinian factions in Gaza. Loay Qarouti of the Popular Front for the Liberation of Palestine General Command said the mediators asked them to protect the lives of protesters and minimise losses among them

The blockade has made it increasingly difficult for Hamas to govern. Widespread desperation among Gaza's 2 million residents - who get only a few hours of electricity a day and undrinkable tap water, in addition to suffering from soaring joblessness and limited freedom of travel - fuels their participation in the protests

Since the marches began six months ago, at least 210 Palestinians present or taking part in the protests have been killed and more than 18,000 were wounded

Israel has come under heavy international criticism for what many see as excessive use of force and the large number of unarmed people who have been shot

In the West Bank, a 33-year-old Palestinian man was killed and nine others wounded by live rounds, one in critical conditions, as the Israeli forces confronted stone throwers in a village near Ramallah city, doctors said