JERUSALEM (AP) -- An explosion ripped through a bus on a main highway in Israel's north on Thursday, and police said at least three people were killed.
An eyewitness, Emanuel Biton, told Army Radio he was driving behind the bus and that he saw the blast "rip the bus into pieces, and things were flying everywhere." The bus was not full when the explosion happened, he said.
Army Radio said the bomb was apparently carried by a Palestinian suicide bomber, but police said it was too early to determine.
Another eyewitness, Sadi Ovadia, told Israel TV "There was nothing left of the bus" after the blast.
The bus was near an Israeli military base when the bomb went off, but it was nonmilitary.
Ambulances and police vehicles raced to the scene. Police commander Moshe Waldman told Israel Radio said three people were killed on the vehicle and that six others were injured, two critically.
The attack came as U.S. envoy Anthony Zinni was holding talks with Israeli and Palestinian leaders, trying to cement a truce to end the fighting.
Dore Gold, an adviser to Israeli Prime Minister Ariel Sharon, said, "unfortunately, there is no letup in the wave of terror against the state of Israel." Sharon was about to leave for the United States when the bomb went off on the bus. It was not immediately known whether he would postpone his trip because of the attack.
Earlier, two Palestinians were shot and killed by Israeli forces at a West Bank roadblock, and at another roadblock, not far from the site of the bus attack, an Israeli was killed and another was seriously wounded in a drive-by shooting attack at a roadblock at the edge of the West Bank.
Israeli security forces have been on alert for attacks by Palestinian militants throughout 14 months of Palestinian-Israeli violence. Suicide attacks have taken the lives of dozens of Israelis and wounded hundreds during the fighting.
At the scene, Issachar Toami, the local fire department commander, said that all the wounded had been taken to a local hospital. Police did not immediately board the blown-out bus, he said, because of the possibility that additional explosives might still be inside it.
The road where the explosion took place runs east to west through northern Israel, from Hadera near the coast to Afula, near the Jordan River valley. On Monday, two Palestinian gunmen entered Afula, which is near the West Bank, and opened fire, killing two Israelis. Police shot the attackers dead.