TEL AVIV, Israel, Aug. 4 (UPI) -- Two Israelis were shot and killed in the West Bank early on Monday while driving on a road north of Ramallah, police said.
The pair -- a husband and wife -- were killed near the Jewish settlement of Shilo, and two others in the car were wounded. In a separate incident two Palestinians were killed after exchanging fire with Israeli soldiers in the village of Burka near Nablus.
The deaths came after a day of violence on Sunday, in which at least 13 people were killed in several attacks by Palestinians militants on Israelis.
In the worst single incident of Sunday, at least nine people were killed and dozens injured in a suicide bomb attack, which destroyed a bus in northern Israel.
A police spokesman said they believed but were not certain that a male suicide bomber set off powerful explosives as the bus was approaching a stop.
The militant Hamas movement claimed responsibility.
"Today's attack is the second chapter of the movements' retaliation on the assassination Salah Shehada, the founder and the leader of Izel Dein Al Qassam, the armed wing of Hamas in Gaza," a leaflet distributed by the movement in Gaza said.
Mahmoud Al Zahhar, a Hamas spokesman in Gaza, said the attack was "in revenge for the crimes that the Zionists are carrying out on daily bases against our people."
He said Ized Dein Al Qassam delivered a leaflet without mentioning the name of the bomber in fear that the Israeli army would blow up his house and deport his family.
The bus, on route 361, left Haifa at 7:15 a.m. local time and picked up passengers in many places along the way. Egged Bus Co. spokesman Doron Ratner said the Haifa terminal was well protected but noted the bus stopped to pick up passengers near several Arab villages along the way.
The blast ripped the roof and the side of the bus near Meiron, a few minutes' drive along a winding, narrow road to Safad. Some of the people who were waiting at the station were also wounded.
From her hospital bed, Oshrat Amiram, who was waiting at the Meiron junction bus station, said because of the crowd there she hailed a taxi and as she asked him how much the ride would cost, heard the blast.
"I turned back and saw everything in flames. Soldiers fell on the ground," she said. "One soldier had flesh all around, tissue on his body. Everybody began to scream and run and I ran too and fell on the road. Somebody from my village took me to the hospital."
Arnon Ben-Harouch, a medic who boarded the bus said some of the people there were dead but a pregnant woman was caught between seats, dazed. With the help of another medic and a policeman they pushed a chair away and got her out.
The Ziv hospital in Safad said it received 45 wounded, but some whose wounds were severe were taken by helicopter to Haifa.
Two of those killed in the bus bombing were Philippine citizens, authorities said.
The Palestinian Authority condemned the attack, calling it "terrorist and violent," but said it was caused by Israel's operations in the West Bank and Gaza that had weakened the Palestinian security apparatus.
"The Israeli actions over the last few months against the Palestinian Authority had weakened its security and police forces to act in the territories and prevent more violence," it said a statement distributed on the official Wafa news agency.
Israeli says Palestinian leader Yasser Arafat has not issued clear directives to stop the violence and that Palestinian security forces were responsible for some attacks against Israeli targets.
Arafat decided "to launch terror to break our will power and we are in the midst of this struggle," said Maj. Gen. Amos Gilead said. He added that Arafat "prevents the mergence of any capability to prevent this terror."
President Bush said he was "distressed" by the ongoing violence.
"We must do everything we possibly can to stop terror," he said early Sunday as he began a round of golf in Kennebunkport, Maine. "There are a few killers who want to stop the peace process. I call upon all nations to do everything we can to stop these terrorist killers."
The bus blast came four days after a bomb exploded at a cafeteria in the Hebrew University's campus on Mount Scopus in Jerusalem, killing five U.S. citizens and two Israelis. Hamas also claimed responsibility for that blast.
The intensified action by Hamas follows Israel's killing of Shehada, the head of its armed wing, two weeks ago. Fourteen people were killed in the attack, nine of them children. After his killing, Hamas said would avenge his killing by carrying out 10 suicide bombing attacks to kill 100 Israelis.
Israel said Shehada was responsible for hundreds of attacks in which hundreds of Israelis were killed and wounded and that he had been planning several "mega attacks."
In the second incident, three people were killed and at least 16 were wounded in the shootout with police near the Damascus Gate in Jerusalem's Old City. Police said a militant fired at a telephone company truck, killed its guard, wounded the driver and another passenger. Border Policemen stormed the site, killed the gunman but a passerby was also killed. Several people were reportedly knocked over when the policemen ran to the site.
Chris Williams, of Boston, said he saw a person point a gun to the head of a man sitting in the truck. "We started running away," he said, then heard "two to three shots and then a lot of automatic fire."
An East Jerusalem resident who was at the al-Umar cafeteria was also killed. He appears to have been in the policemen's line of fire.
In other incidents, Israeli soldiers shot and killed a gunman who swam to the northern Gaza Strip and approached a settlement.
Near the west Bank town of Tulkarim, militants overtook a car, opened fire and severely wounded a soldier. Another soldier and a civilian were also wounded. A bomb placed on a road west of Beit-El in the West Bank also exploded, wounding four soldiers, settler and medical sources in the area said.
In its bid to end the attacks, Israel has moved tanks and troops into several West Bank towns and villages.
On Sunday, it destroyed two houses belonging to the families of suicide bombers in the West Bank town of Hebron, witnesses said. Six houses were demolished in the villages of Qabatia and Selat El Dhaher near Jenin.
The Israeli government approved a military plan to destroy the house of Palestinian suicide bombers and deport their families from the West Bank to the Gaza Strip, but gave the slated deportees a opportunity to fight the move in an appeals committee comprising a judge and officers and, if they fail there, at the High Court of Justice. The case is now before the appeals committee.
U.S. Secretary of State Colin Powell is due to arrive in the area shortly, where he planned to meet with Palestinian officials in pursuit of a Middle East peace process.
(Saud Abu Ramadan in Gaza contributed to this report)