JERUSALEM (AP) — Dozens of Jewish West Bank settlers clashed with Israeli security forces on Tuesday, hurling stones and bottles at the officers in one of the most serious confrontations with militant settlers in years.

The violence was sparked when large numbers of Israeli police and paramilitary units arrived to the settlement of Yitzhar in the northern West Bank to carry out a court-ordered demolition of several structures in the early morning hours. They were met by a crowd of settlers who tried to thwart the building removal.

“They were doing everything they could in terms of preventing units from working there and at the end, it turned into a full-scale incident,” said police spokesman Micky Rosenfeld. He said police dispersed the settlers using stun grenades and other non-lethal weapons and that six police officers were injured slightly by the stones.

Rosenfeld said the rioters also tore down a small military encampment located near the settlement. Israeli Channel 2 TV reported that gasoline was poured around the tents but that none of the soldiers stationed there was injured.

The incident comes after suspected settlers twice this week slashed the tires of cars belonging to military personnel visiting Yitzhar, one of the most militant settlements, whose residents have repeatedly been involved in clashes with Palestinian farmers.

Following the attack on the cars, Israeli Prime Minister Benjamin Netanyahu said Israel would act with “zero tolerance,” calling the act “reprehensible,” while his defense minister, Moshe Yaalon, called it “terror for all intents and purposes.”

Yaalon said Tuesday’s violence would be treated with “utmost gravity.” Netanyahu instructed his defense minister to act against the “outlaws,” according to a statement from his office.

Gadi Shamni, a former military general who served as commander over the West Bank, said Israel lacked political will to properly battle settler violence.

“They call it terror but they don’t fight against it as we know how to fight against terror,” he told Channel 2.

The rampage comes as Israel and the Palestinians are attempting to get U.S.-mediated peace talks back on track, which appeared in recent days to be headed for collapse. After Israel failed to carry out a planned prisoner release, the Palestinians retaliated by signing letters of accession for 15 international conventions.

Under the terms of talks renewed in July under heavy U.S. pressure, Israel had promised to release 104 long-held Palestinian prisoners in four groups. The Palestinians said they would suspend a campaign to sign up the “state of Palestine,” recognized by the U.N. General Assembly as a non-member observer state in 2012, for as many as 63 U.N. agencies, treaties and conventions.

On Tuesday, Israeli Foreign Minister Avigdor Lieberman warned the Palestinians that the prisoner release will not happen as long as they pursue what he called a “provocative” bid to join U.N. agencies.

Lieberman also accused the Palestinians of breaking the terms of the U.S.-brokered peace talks, saying they should “pay a price” for this.

Lieberman said the final prisoner release was off the table unless the Palestinians reversed course on the U.N. bids.

“We are in favor of negotiations but the previous offer about releasing prisoners doesn’t exist anymore,” Lieberman told Israel’s Army Radio on Tuesday. “Whoever broke the rules has to bear responsibility … therefore the previous offer is not relevant anymore.”

Mohammed Ishtayeh, an aide to Abbas, said on Monday that the letters of accession will not be withdrawn and that the step is irreversible. He said the Palestinians were ready to widen their bid.

Palestinian Foreign Minister Riyad Malki said Arab foreign ministers would convene in Cairo on Wednesday to discuss the breakdown in talks and Abbas will ask them for political and financial support.

The crisis in talks has also spurred U.S. Secretary of State John Kerry, who has made more than 10 trips to the region in his attempt to secure a deal, to say the U.S. would rethink its mediator role.

Kerry originally hoped for a peace deal by April 29.

But after months without progress in the Mideast negotiations, he lowered his sights, saying he sought a framework deal by that date. In recent weeks, negotiations focused on reaching agreement on extending the talks into 2015.