Israeli and Palestinian forces arrested seven men today over a suicide bombing at a Tel Aviv nightclub that killed four Israelis and endangered Middle East peacemaking efforts.
In some of the strongest Palestinian condemnation of an attack during more than four years of bloodshed, President Mahmoud Abbas called the bombers "terrorists" and blamed outsiders opposed to his two-week-old ceasefire with Israel.
"We will bring them to justice. We will not allow anyone to sabotage the ambitions of our people," Mr Abbas told reporters.
The bombing last night shattered several weeks of calm after a de facto truce by militants, who have yet to formalise the ceasefire agreed between Mr Abbas and Israeli Prime Minister Ariel Sharon at a groundbreaking February 8th summit.
Ambulances rushed to the popular karaoke club in a scene of flashing lights and blood-stained pavement that many Israelis had begun to believe they had put behind them. Pieces of flesh were sprayed on parked cars.
Hospital officials said the bomber killed at least four people and some 50 were wounded.
Israeli troops pushed into the West Bank village of Deir al-Ghoson before dawn, grabbing five men, including two brothers of the suspected bomber. Palestinian forces later picked up two men believed to have links to Islamic militants.
Israeli officials said the bombing proved that the Palestinian strategy of trying to win over the militants to ratify the truce had failed and tougher action was needed.
"Words are not enough. We must see action," said Mr Gideon Meir of Israel's Foreign Ministry. "We must see arrests, collecting illegal weapons from those terrorist organisations ... The only language they understand is force."
Mr Sharon was to consider Israel's response to the bombing at a meeting with security chiefs today.
Responsibility for the attack, the first suicide bombing in Israel in nearly four months, remained unclear.
A cell of the militant Islamic Jihad group in the West Bank claimed the attack, but the faction's leadership in the Gaza Strip denied any knowledge and said it would continue to maintain calm. Other mainstream groups also denied any role.
Israeli media said Lebanese Hizbollah guerrillas, who have recently come under Palestinian suspicion, may have had a hand in the bombing to try to stop peace efforts. There was no immediate comment from the Iranian-backed group.
Mr Abbas said "there is a third party which wants to sabotage this process" but did not point a finger directly at Hizbollah.
The family in Deir al-Ghoson announced through loudspeakers that Abdullah Shelbayeh "had carried out a martyrdom operation".
But there was little sign of the celebration that often followed bombings.
US Secretary of State Condoleezza Rice demanded that Palestinian leaders find those responsible and "send a clear message that terror will not be tolerated".