The Palestinian Authority has condemned Tuesday's shooting attack that left four Israeli citizens dead near a settlement close to Hebron in the occupied West Bank.

"What happened tonight in Hebron was timed to coincide with the PLO's decision to engage in negotiations to end the occupation and achieve freedom and independence for our people," Prime Minister Salam Fayyad said.

"We condemn this operation, which runs counter to Palestinian interests and against efforts of Palestinian leadership to mobilize international support for the rights of our people as well as with previously signed agreements," Fayyad told Ma'an shortly after the attack.

Palestinian gunmen opened fire on a car driving east of the illegal Kiryat Arba settlement near Hebron at 6:30 p.m, army officials said. The victims were related and included a pregnant woman, the Israeli military said.

The attack came hours after 10 armed settlers opened fire at three Palestinian teenagers as they tended to their land in the Salfit district village of Deir Istiya, the mayor said. There were no reports of injury.

The Ramallah-based prime minister called on all Palestinians to categorically renounce violence and protect the legitimacy of the peaceful resistance movement against the settlements and other Israeli practices.

"This is the path to salvation, not exploiting the suffering of the Palestinian people in the service of class and regional agendas contrary to the interests of our people with slogans devoid of meaning," Fayyad said.

He warned against "being sucked into a spiral of violence. Our people know through extensive experience what serves practical and higher national interests. This is why it is natural to join forces to reject the occupation by renouncing violence in all its forms."

Hamas praised the "heroic" attack, and its militant wing later claimed responsibility.

Earlier, a Palestinian group calling itself the Al-Haq ("Rights") Brigades has claimed responsibility.

In a statement to Ma'an, Al-Haq said its operatives successfully fled capture. The attack comes in response to the PLO's decision to return to direct negotiations with Israel, the statement said.

PLO officials were en route to Washington at the time of the attack.

Israel's commander of the Judea and Samaria (West Bank) Regional Brigade, Brig. Gen. Nitzan Alon, said, "The investigation is still underway. We were on high alert in light of the upcoming holiday period but regretfully, we were unable to prevent the attack. We will continue to be on high alert in the area."

Alon said in a statement distributed by the Israeli army that "as far as we can tell, the Hamas terror organization is behind the attack. ... The forces are currently searching the area for the terrorists responsible."

Fayyad stressed that Tuesday's attack took place in an area of the West Bank controlled by the Israeli military and falls outside of the PA's security responsibilities under the Oslo Accords.

The PA will continue to take "all measures to prevent the reoccurrence of such events in order to demonstrate the government's ability to ensure security," he said.

Americans for Peace Now, a Washington-based group which opposes settlements, condemned the attack.

"Today's attack is a senseless act of violence whose likely purpose is to derail the peace talks that are set to get underway in Washington," director Debra DeLee said in a statement.

"There are no doubt self-appointed spoilers who want to force both Israelis and Palestinians to spurn negotiations in favor of continued conflict. They cannot be permitted to succeed," she said.