Quotes of the Day

It was no doubt inevitable, but that only made it more depressing. A Palestinian suicide bomber shattered the region’s three-month period of calm Friday night by killing four Israelis and injuring 50 outside a crowded Tel Aviv nightclub. The bomber, a 21-year-old student from a village near the West Bank town of Tulkarem, was the first since the November death of Yasser Arafat; he hoped to destroy the tenuous trust that took root at a Feb. 8 peace summit in Egypt.

To keep him from succeeding, Palestinian security forces — which in the last four years have done little or nothing to apprehend those involved in such strikes — reacted energetically. The Palestinian police arrested two people in the West Bank; Palestinian President Mahmoud Abbas ordered his forces to find out which group was behind it; and Palestinian security officials confirmed that the bomber, Abdullah Badran, was a member of Abbas’s own Fatah faction of the P.L.O.

But Fatah’s Aqsa Martyrs Brigades militia denied involvement, as did Hamas. Suspicion fell on Hizballah, the Lebanese fundamentalist group, but on Saturday Islamic Jihad claimed responsibility. Palestinian observers say Islamic Jihad — which like Hizballah gets backing from Iran — may have been pressured by the Lebanese group to claim the attack. Officials say Hizballah wants to kill the trust between Abbas and the Israelis. Abbas didn’t accuse Hizballah directly, but said “there is a third party that is interested in sabotaging this period of quiet.”

Israeli politicians have thus far restricted themselves to urging the Palestinians to track down those responsible. (Late Saturday, Defense Minister Shaul Mofaz accused Syria of involvement; Damascus denied the charge.) If that restraint holds, perhaps the spirit of co-operation still has a chance to survive.

• MATT REES and JAMIL HAMAD
• A new suicide bombing puts the commitment to peace under strain