GAZA CITY, Gaza Strip (AP) _ The Palestinian intelligence chief, an ally of moderate President Mahmoud Abbas, was seriously wounded by a bomb packed with metal pellets at his headquarters Saturday in what security officials called an assassination attempt.

There was no claim of responsibility, but the explosion in an elevator shaft of the heavily guarded compound in Gaza City came at a time of growing friction between Abbas and the Hamas-led government over control of the security forces.

The intelligence chief, Tareq Abu Rajab, is a top official in Abbas' Fatah movement. Fatah did not openly accuse Hamas, but Abu Rajab's deputy did not rule out the Islamic militant group's involvement.

Other Fatah members demanded Abbas dissolve the Hamas-led government and call early elections.

Abbas called the blast ``unfortunate'' and said it posed a ``grave danger'' to the Palestinian Authority.

Tawfiq Tirawi, Abu Rajab's deputy, said Hamas was responsible for a previous assassination attempt two years ago that seriously wounded Abu Rajab.

Asked if Hamas also was behind Saturday's attack, Tirawi said: ``Everything is possible. I don't rule anything out for now.''

The bomb exploded before noon Saturday. Abu Rajab and six aides and bodyguards got into an elevator and were close to the second floor when the bomb exploded. A bodyguard was killed immediately, and Abu Rajab and five others were seriously wounded.

The explosion wounded three others, including a secretary riding in an adjacent elevator, doctors said.

Abu Rajab underwent surgery at nearby Shifa Hospital in Gaza, where doctors stopped the bleeding and stabilized him before transferring him to Israel's Ichilov Hospital in Tel Aviv.

With his head bandaged and in a neck brace, he was taken in a heavily guarded Palestinian ambulance to the Israel-Gaza border crossing.

Lying on a bloody sheet, he was rolled on a gurney from the Palestinian ambulance to the waiting Israeli vehicle. Israeli medical personnel immediately treated Abu Rajab before putting him in the ambulance and taking him to Ichilov.

The other wounded were taken to Shifa Hospital in cars of the intelligence service. Fellow agents fired in the air from the windows of the vehicles to clear the way. Several members of a new Hamas militia fired toward the vehicles, possibly because they believed they were coming under attack, witnesses said.

The initial investigation by Palestinian security forces loyal to Abbas found that a homemade bomb packed with metal pellets was planted under the elevator's floor, Tirawi said.

The explosion caused massive damage, and bomb experts were sent to the scene to investigate.

Khaled Abu Hilal, spokesman for the Hamas-controlled Interior Ministry, initially suggested the blast was set off when one of Abu Rajab's bodyguards inadvertently dropped a hand grenade. However, Abu Hilal later said that comment was based on inaccurate information.

The intelligence service said the blast was caused by a bomb and that Abu Rajab was the target of an assassination attempt.

Some Fatah members demanded that Abbas dissolve the Hamas government and call a new election. The 2,000-member intelligence service and most members of the security forces are loyal to Abbas.

A group calling itself the Fatah Protection Unit demanded that Hamas disband its 3,000-strong militia within three days. The militia was deployed earlier this week, despite Abbas' vehement opposition.

If the militia is not removed, ``we are ready to deploy our men and our fighters in the streets ... to protect Fatah men and all of Palestinian society,'' the statement said.

Palestinian Prime Minister Ismail Haniyeh of Hamas canceled all appointments for Saturday and formed a committee to investigate the incident, government spokesman Ghazi Hamad said.

``We are asking not to make early judgments, accusations or responses that might lead to tension in the Palestinian streets,'' said Hamad, in apparent anticipation of Hamas being blamed.

Abu Rajab, a key Abbas ally, was sent by the Palestinian president to Jordan last week to look into suspicions of officials there that Hamas was trying to smuggle explosives into the kingdom and carry out attacks.

Abu Rajab also has been involved in security coordination with the United States and Israel. He survived an assassination attempt two years ago when gunmen fired on his convoy. Two of his bodyguards were killed.