Palestinian police arrested three suspected militants and hunted for two more over the killing of three U.S. security guards in the Gaza Strip, Palestinian security sources said on Thursday.

They announced the arrests as international pressure mounted on Palestinian authorities to crack down on militants after the bombing of an American diplomatic convoy.

It was the first to kill Americans during a three-year-old Palestinian uprising against Israel for statehood.

The U.S. guards were killed when a bomb, set off apparently by remote control, wrecked their armored jeep on Wednesday.

Five investigators from the U.S. Federal Bureau of Investigation (FBI) arrived in the region, a spokesman for the U.S. embassy in Israel said. "They are going about their work on the ground and expect to go into Gaza at some point."

Palestinian security officials said they were making headway in their investigation into the attack and that it was possible the bombers had links with a foreign group, such as Lebanese guerrillas backed by Iran and Syria.

"People behind the attack could either be linked to some group abroad such as Hizbollah or Iran's Revolutionary Guard who partially fund and support the Popular Resistance Committees," one senior Palestinian official said.

Hizbollah has no branch in the Palestinian areas but "it does have links with some individuals here," the official said. "The state of total chaos and the power vacuum in Palestinian areas makes us believe that all options are possible," he said.

According to Palestinian security sources, three men they have detained since Wednesday belonged to the Popular Resistance Committees, an umbrella group of militants that carried out previous roadside bombings against Israeli forces.

THREE DETAINED

"A few hours after the bombing...Palestinian security forces detained three people as part of the investigation conducted by the Palestinian Authority into the incident," a security official told Reuters in Gaza.

All three were rounded up in the Jabalya refugee camp, a militant hotbed next to the site of the attack, they said.

Two more members of the group were being sought and an attempt to arrest one of them in the nearby town of Beit Lahiya sparked a gunbattle between militants and security forces during which he escaped, the sources and witnesses said.

Seven Palestinians -- two of them policeman -- were wounded in the shoot-out, local medics said.

A leader of the Popular Resistance Committees, many of whose followers used to be part of the Islamic militant group Hamas or Palestinian President Yasser Arafat's Fatah movement, confirmed the arrested men were members but denied any involvement.

The United States, the United Nations and European Union blamed lax Palestinian security for the bombing and demanded reforms by Palestinian authorities to rein in militant violence, a central requirement of an internationally backed peace plan.

Arafat said he had taken "concrete" action, alluding to the arrests. "We sent our security groups (to investigate) and from yesterday we did not sleep...There is something concrete which we have done," he told reporters at his West Bank compound.

"I'm saying (we have done) 'something' -- (although) not all we are looking for," he said, speaking in English. "We are condemning it (the attack) completely. It is very serious, dangerous and not only against the Americans, but against the Palestinians before it is against the Americans."

'ATTACK ON ISRAEL'

Israeli Defense Minister Shaul Mofaz told reporters that "we are treating (this) like an attack on the Israeli army, and will do everything we can to get our hands on the perpetrators."

Caskets containing the remains of the three slain Americans, John Branchizio, 37, Mark Parson, 31, and John Martin Linde, 30, were flown home to the United States for burial.

At a ceremony at Ben-Gurion Airport outside Tel Aviv, U.S. Ambassador Daniel Kurtzer said the men were "killed on a mission of peace."

On Thursday night, the Israeli army said it was lifting travel restrictions clamped on Palestinians in the Gaza Strip who had been denied access to key roads due to security concerns over the Jewish holidays.

In Gaza's Rafah refugee camp, three Palestinians died in gunbattles with Israeli forces who have staged a week-long hunt for tunnels used by weapons smugglers near the Egyptian border.

Two Palestinian men were killed in clashes on Thursday and a third died of injuries sustained last Friday, hospital officials said. Another nine people were wounded on Thursday in Rafah, including four under the age of 18.

Prime Minister Ariel Sharon's office said Israeli security forces arrested an officer in the coast guard of the Palestinian security forces in early September on suspicion of smuggling arms from Egypt and selling them to West Bank security forces.

Sharon threatened anew in a speech in southern Israel on Thursday night that if the Palestinians failed to rein in militants "there will be no Palestinian state," as prescribed by the U.S.-backed "road map" peace plan.

He added that Israel would pursue a war "against terrorism everywhere, without hesitation."

(China Daily October 17, 2003)