HAIFA, Dec 2: A Palestinian suicide bomber killed at least 15 people and wounded dozens when he blew himself up on a bus in northern Israel on Sunday, hours after a double suicide attack killed 10 people in Al Quds.

The bombings were among the deadliest attacks in Israel in years and marked one of the bloodiest phases of a 14-month-old Palestinian uprising against Israeli occupation. They threatened to wreck a new US peace mission led by envoy Anthony Zinni.

President Yasser Arafat’s Palestinian Authority, under intense US pressure to crack down on radical groups, declared a state of emergency and ordered its security forces to arrest militants who had planned and carried out the attacks.

Leading fierce international criticism of the attacks, US President George W. Bush condemned the bombings before talks with Israeli Prime Minister Ariel Sharon in Washington.

“This is a moment where the advocates for peace in the Middle East must rise up and fight terror. Chairman Arafat must do everything in his power to find those who murdered innocent Israelis and bring them to justice,” he said.

A senior Palestinian security source said dozens of militants had been arrested since Saturday night in the West Bank and Gaza Strip.

The Israeli army responded to the bombings by announcing it was tightening its blockade of the West Bank by encircling Palestinian cities it had not already surrounded because of “numerous warnings of future attacks”.

In a nightmarish sequel to Saturday night’s suicide bombings in Al Quds, a Palestinian boarded an inter-city bus in the port city of Haifa and blew himself up seconds later.

The explosion tore the roof off the bus, shattered windows and spread bodies and mangled body parts across a street in a residential area. Medical officials said at least 15 people were killed and 40 wounded, 17 of them seriously.

“Such was the force of the blast that the victims — both those who died and those who were wounded — didn’t utter a word, not even a cry for help. There was complete silence,” witness Arieh Zisso told Israel radio.

The Palestinian Authority condemned the bombings, which it said were intended to foil peace efforts.

ATTACKS IN SUCCESSION: The rapidity of the attacks reminded Israelis of a series of suicide bombings in rapid succession in early 1996 which killed dozens of Israelis in response to Israel’s killing of a top Hamas bombmaker with a booby-trapped cellphone.