© AFP/File John Thys

BRUSSELS (AFP) - Israelis and Palestinians should avoid "provocative actions" which could derail direct peace talks, the European Union's chief diplomat said Thursday after a flare-up of violence.

EU foreign policy chief Catherine Ashton praised Israeli Prime Minister Benjamin Netanyahu and Palestinian president Mahmud Abbas "for their vision and political courage" as they prepared to resume negotiations.

She said the outcome of their talks would be "crucial" for both sides and the whole Middle East.

But the killing of four Israelis near a West Bank settlement, an attack claimed by the Islamist militant group Hamas, "shows that there are forces in the region which are determined to undermine the peace process," Ashton said.

"We must not allow them to succeed. Supporters of peace must persevere through difficult times," she said in a statement.

"It is very important that all relevant parties avoid provocative actions which could undermine the success of the talks."

Ashton added: "This attack underlines, above all, the urgency of a two-state solution with the State of Israel and an independent, democratic, contiguous and viable State of Palestine, living side by side in peace and security with each other and their neighbours."

Abbas and Netanyahu were to resume direct talks in Washington on Thursday following a 20-month hiatus.

Ashton reiterated hopes expressed by a quarter of international powers that the two sides would conclude negotiations within one year, adding that the talks "should focus on all final status issues."

The European Union is a member of the Middle East Quartet, along with the Russia, the United States and the United Nations.

Ashton was invited to an informal dinner ahead of the talks in Washington, but was unable to attend due to a previously scheduled trip to China.