Updated

Israeli forces shot dead four Palestinian youths Friday, Gaza's Health Ministry said, a deadly escalation after two prior weekly protests along the perimeter fence between Gaza and Israel saw no fatalities.

The bloodshed is likely to complicate the mission of Egyptian mediators, who intensified their shuttle diplomacy to achieve calm and prevent a full-blown conflict between Gaza's Hamas rulers and Israel.

Thousands of Palestinians gathered at five locations along the boundary, burning tires and throwing rocks and firebombs at Israeli troops who respond with tear gas and occasional live fire.

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

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

The militant Hamas group has scaled down the deadly protests over the past two weeks as Egypt stepped up its efforts to secure calm.

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 minimize losses among them."

Egypt wants calm restored to achieve national Palestinian reconciliation between Hamas, which seized Gaza in 2007, and the West Bank-based administration of President Mahmoud Abbas.

But Hamas maintains it wants a full lifting of a crippling blockade Israel and Egypt imposed on Gaza to isolate the Islamic movement.

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 Hamas-orchestrated protests.

Since the marches began six months ago, at least 160 Palestinians present or taking part in the protests have been killed. A Gaza militant fatally shot an Israeli soldier in July.

Israel accuses Hamas of using the large protests as cover to stage border infiltrations and attacks. It says it is defending its border and accuses Hamas of exploiting young protesters and encouraging them to risk their lives in order to increase pressure to ease the blockade.