A bomb exploded near a road outside the West Bank city of Hebron on Tuesday, injuring three Israeli teen-agers about to board a bus after picking cherries, Israeli radio and a Jewish settler group said.

Elsewhere in the West Bank, the Israeli army staged a new raid on the town of Tulkarem and maintained a siege at Palestinian leader Yasser Arafat's battered compound in Ramallah for a second day.

The violence coincided with a Washington visit by Israeli Prime Minister Ariel Sharon, who received strong backing Monday in a meeting with President Bush. Sharon planned talks with U.S. congressional leaders, who have also been supportive of Israel in the Mideast fighting.

The bomb blast occurred as about 40 Israeli teen-agers who had picked cherries were boarding a bus south of Hebron near the adjacent Jewish settlement of Kiryat Arba, according to the Settlers' Council and Israel radio.

Three 15-year-old boys were taken to Hadassah Ein Kerem Hospital in Jerusalem to be treated for leg, arm and chest wounds, the hospital said. One was seriously injured.

In nearby Hebron, Palestinian police said they found the bodies of two Palestinians suspected of providing Israel with information that helped the army kill a local militia leader. The Al-Aqsa Martyrs Brigade -- a militia group affiliated with Arafat's Fatah faction -- claimed responsibility for Tuesday's killings.

Police said they found spent cartridges close to the bodies, one of which was discovered in the exact spot where Marwan Zalloum -- the local leader of the militia -- was gunned down by an Israeli helicopter on April 22.

In its leaflet, the militia claimed the two men had helped Israel track down Zalloum. Dozens of suspected collaborators have been killed since the Palestinian uprising began 20 months ago.

In the Gaza Strip, Israeli soldiers saw an explosion along the fence dividing the coastal strip from Israel. After a search, they found the body of a Palestinian who was apparently planting a bomb that exploded prematurely, the army said.

In Tulkarem, about 10 Israeli tanks and 15 jeeps entered the West Bank city and several nearby Palestinian villages, conducting searches and preventing residents from leaving their homes. The army said soldiers were looking for militants, though no arrests were reported.

The Israeli army also carried out a brief incursion overnight into the Dheisheh refugee camp in Bethlehem.

The Israeli army has been conducting almost daily in-and-out raids of Palestinian towns and villages in the West Bank.

The incursions -- which follow a wide-scale military operation in the West Bank that ended in May -- are often brief, sometimes lasting just a few hours. The army says the raids are meant to thwart suicide bombings.

Israeli troops entered Ramallah in force early Monday, encircling Arafat's compound and clamping a curfew on the Palestinian commercial hub.

The army said it has detained more than 30 suspects in Ramallah, including a suicide bomber who was preparing to attack. Yusef Tarifi, the son of Palestinian Civil Affairs Minister Jamil Tarifi, was among those arrested overnight, a relative said.

Soldiers have also found two car-bombs containing a total of 135 pounds of explosives, a spokesman said.

The army said it was encircling Arafat's compound to prevent gunmen from seeking refuge there. It did not attack the headquarters itself as it did last Thursday, when soldiers blew up three buildings in retaliation for the suicide bombing a day earlier.

Arafat remained inside the compound Tuesday and was unharmed, Palestinian officials said.

Outside his headquarters, the army blocked roads with earthen barricades and piles of rubble. Streets remained deserted and the army prevented journalists from entering the city, which it declared a closed military zone.

In another development, Majed al-Masri, a West Bank leader of the Al Aqsa Martyrs' Brigade -- a group affiliated with Arafat's Fatah movement -- said the militia had decided to halt attacks in Israel for the time being. But the militia would continue to attack Jewish settlements and military posts in the West Bank and Gaza Strip, he said.

"We want to let the current peace efforts take their course," Masri told the Associated Press, adding that if the army kills any Palestinian militant leaders, the group would resume its attacks inside Israel.

In Washington, Bush supported Israel's "right to defend herself" after his meeting with Sharon. The Israeli leader reiterated his position that violence must end before peace negotiations can begin. He also stressed again his belief that there can be no successful talks so long as Arafat remains in power.

Meanwhile, Palestinian Information Minister Yasser Abed Rabbo alleged that the Israeli raids were part of Sharon's attempt to undermine "the reform process."

The incursions came a day after Arafat announced a revamped Cabinet, which was to hold its first meeting Monday at the compound. The session was canceled.