JEBALIYA REFUGEE CAMP, Gaza Strip – Palestinian authorities began making arrests Thursday in a deadly attack on a U.S. diplomatic convoy, detaining seven militants from a rogue group that includes former members of the Palestinian security forces.
Palestinian police briefly exchanged fire with militants in two of the raids, security officials said. The arrests came as an FBI team arrived in the region to lead the investigation into Wednesday's bombing, which killed three American security guards and wounded a fourth.
U.S. Embassy spokesman Paul Patin said the FBI team had begun an "open-ended" investigation. He said he did not have details of the probe, but added, "I'd imagine it might involve going to the site." American investigators were forced to flee the scene of the bombing Wednesday after being attacked by stone throwers.
The suspects arrested Thursday are members of the Popular Resistance Committees, a group of dozens of armed men from various factions, many former members of the security forces and disgruntled followers of Yasser Arafat's Fatah movement (search).
A Palestinian source said none of the suspects had been in the security forces Arafat controls, but the group's links to the security forces could prove embarrassing to Arafat.
Israeli officials said the group, formed after the outbreak of Israeli-Palestinian fighting three years ago, has ties to the Lebanese guerrilla group Hezbollah (search). The Palestinian group has blown up three Israeli tanks with massive remote-controlled bombs in the past two years -- the same technique used in Wednesday's attack.
No Palestinian group has claimed responsibility for the bombing, the first deadly attack targeting Americans in the Palestinian areas. The bombing was likely to increase U.S. pressure on the Palestinian leadership to move against militants.
Speaking to Israel Radio, Arafat security adviser Jibril Rajoub promised a thorough investigation. "I am 100 percent sure that we will be able in the coming days to reach who planned and carried out this attack," he said.
In an apparent nod to the United States, Arafat placed all nine Palestinian security units in the Gaza Strip under a single commander, Maj. Gen. Abdel Razek Majaidie. The United States has demanded reforms in the Palestinian Authority (search) -- especially in the security forces -- and a crackdown on militant groups.
Palestinians often accuse the United States of siding with Israel, but officials are careful not to cross the line of open hostility to Washington. Arafat and Palestinian Prime Minister Ahmed Qureia condemned Wednesday's bombing.
"It's clear that it is very serious and dangerous, not only against Americans, but against all Palestinians," Arafat said Thursday.
The attack could lead to a further U.S. disengagement from the conflict and deter the international community from sending large numbers of monitors -- a long-standing Palestinian request.
Also Thursday, Israeli forces backed by 50 armored vehicles raided another section of the Rafah refugee camp on the Gaza-Egypt border in search of weapons-smuggling tunnels. It was the third army raid of a Rafah neighborhood in a week.
A member of the Palestinian security forces and a man identified by local people as a gunman were killed, and 13 people were wounded in sporadic exchanges of fire, hospital officials said. Two minors were among those hurt. Israel also announced the arrest of a member of the Palestinian Coast Guard who allegedly smuggled weapons into Gaza from Egypt.
In Wednesday's attack in Gaza, assailants detonated a remote-controlled bomb packed with dozens of pounds of explosives on the main north-south highway in Gaza.
The three Americans killed were identified as John Branchizio, 36; Mark T. Parson, 31; and John Martin Linde Jr., 30. They had been hired through a contract with DynCorp, a Virginia-based security firm. A fourth guard was treated in Gaza and transferred to an Israeli hospital.
Late Thursday, the bodies of the three were brought to Israel's international airport outside Tel Aviv, for a short memorial ceremony.
The coffins, draped with American flags, lay on a raised platform as diplomats and embassy employees stood quietly on the runway next to the plane, some sobbing silently.
Eulogizing the three guards, U.S. Ambassador Dan Kurtzer said: "They were a credit to their country and to our community. We are proud of them, and we mourn their loss." After the ceremony, the bodies were flown home.
The diplomats in the convoy, escorted by Palestinian police, were heading to Gaza to interview Palestinian academics who were seeking Fulbright scholarships to teach or study in the United States.
Palestinian security officials said Thursday they have a total of seven suspects in custody.
In one overnight raid, in the Jebaliya camp, Palestinian police were greeted by gunfire when they arrived and searched seven homes before making arrests.
Later in the day, officers tried to detain another suspect in Jebaliya, but aborted the mission when they came under machine-gun fire. Security officials said two civilians and two officers were wounded. Several dozen residents took to the streets to protest the attempted arrest.
Hamas, Islamic Jihad and Al Aqsa Martyrs' Brigades, violent groups behind scores of deadly bombings against Israelis, distanced themselves from the attack.
The Popular Resistance Committees were formed at the end of 2000, three months after the outbreak of Israeli-Palestinian fighting. Although they consist mainly of Fatah breakaways and ex-security men, other factions -- including Hamas and Islamic Jihad -- are also represented.
Following the bombing, the U.S. government advised its citizens to leave the Gaza Strip. Between 200 and 400 Americans, some of Palestinian descent, work there.