NABLUS, West Bank, (Reuters) – Israeli soldiers killed six Palestinians on Saturday in the occupied West Bank and the Gaza Strip, in the bloodiest violent outbreak in months.

Three of those who were killed belonged to Palestinian President Mahmoud Abbas’s Fatah movement, and his top aide accused Israel of inflaming tensions and seeking to torpedo U.S.-backed efforts to renew stalled peace talks.

The violence came a day before the anniversary of a three-week Gaza war that killed some 1,400 Palestinians and 13 Israelis. Peace talks have been frozen since.

Soldiers shot and killed three Palestinians suspected of trying to infiltrate from Hamas-ruled coastal Gaza, and three West Bank militants accused of shooting to death a Jewish settler on Thursday, an Israeli military spokeswoman said.

A Hamas security source said the three shot in Gaza at daybreak were apparently civilians collecting scrap metal in an industrial zone near the Israeli border.

In the West Bank, soldiers surrounded the homes of three members of the al-Aqsa Martyrs Brigades, a militant group of Abbas’s Fatah group, and killed all three.

The shootings infuriated Palestinian leaders of Abbas’s Western-backed government and threatened to upset a balance of power with Hamas Islamists, who seized Gaza two years ago and continue to seek to widen their influence in the West Bank.

“This grave Israeli escalation shows Israel is not interested in peace and is trying to explode the situation,” Nabil Abu Rdainah, a top aide to Abbas, told Reuters. “Israel is torpedoing international and American efforts to restart peace talks,” Rdainah said.

Palestinian Prime Minister Salam Fayad, a close ally of Abbas, released a statement saying he “strongly condemned” the shootings, which he viewed as an “extreme escalation.” “This is a sad day for Palestinians,” Fayyad added, voicing the hope “we would not be dragged into a circle of violence, chaos and instability” and urging the international community to intervene to avoid further deterioration.

An Israeli military spokeswoman said troops had launched a “pinpointed raid to capture the perpetrators of the shooting attack and during the operation three who were involved in carrying out that attack were killed.”

Israel Radio said the militants were killed after refusing military orders to come out and surrender.

In the raid at an apartment block in Nablus, Israel said at least one of the militants was armed and four rifles and ammunition were found at the scene. Two of those killed had been jailed in the past and one had a brother killed a previous raid.

The settler had been the first Israeli killed in a Palestinian attack in about eight months in the West Bank, in violence that tested Israeli Prime Minister Benjamin Netanyahu’s recent easing of travel restrictions for Palestinians.

Abbas has demanded a halt to Jewish settlement building before peace talks delayed since a Gaza war in January may resume, and has rejected a temporary building freeze announced last month by Netanyahu as insufficient.

The death toll in Saturday’s incidents was the highest of any Israeli-Palestinian confrontation in West Bank land Palestinians seek for a state, since before the Gaza offensive, and the worst fatalities along the Gaza border since March.