CIA Director George Tenet met with Israeli Prime Minister Ariel Sharon on Monday, beginning a tough Mideast mission in which he wants assurances Yasser Arafat will revamp the Palestinian security forces to prevent attacks on Israel.

Sharon has repeatedly said he does not believe the Palestinian reforms will be serious as long as Arafat leads the Palestinian Authority, and had been expected to deliver that message to Tenet.

After arriving on Monday, Tenet also met with Israeli Defense Minister Binyamin Ben-Eliezer, Israel Radio reported. The CIA chief was to meet with Arafat on Tuesday.

Tenet arrived amid a new Israeli-Palestinian confrontation — this one linked to a crisis the United States helped resolve a month ago and involving one of the top Palestinians wanted by Israel.

First, the Palestinian Supreme Court on Monday ordered the release of Ahmed Saadat, a PLO faction leader whose group carried out last year's killing of Israel's tourism minister. Saadat has been under U.S. and British supervision at a jail in the West Bank town of Jericho since May 1, part of a deal that ended a 34-day Israeli siege of Arafat's offices in Ramallah.

Later Monday, the Palestinian Cabinet overrode the court, refusing to release Saadat. The Cabinet said in a statement that it respected the court decision, but could not implement it because "the Israeli occupation forces" had closed the city of Jericho and "threatened to assassinate" Saadat.

There was no immediate Israeli reaction to the reversal. After the court ruled, however, Sharon said, "We will take all the necessary steps so that he will not be released."

In another reminder of the obstacles Tenet faces on his mission, Israeli troops raided the Ain Beit Ilma refugee camp near Nablus, rounding up about 400 men and taking them away for questioning — the fourth straight day troops have searched for militants in that part of the northern West Bank.

The Palestinian security services do little if anything now to rein in the militants, and Israel charges that some Palestinian security personnel have been involved in attacks themselves. The Palestinians say Israeli strikes on their installations and travel restrictions have limited their ability to act — but there is also widespread acceptance that part of the problem is a lack of control.

In advance of Tenet's visit, Arafat has been holding discussions on streamlining his multiple, overlapping security forces, which include about a dozen different agencies. Early Tuesday, Palestinian officials said Arafat had decided to reduce the security structure to six branches: four security forces, plus military intelligence and his personal guard unit. He was to present the plan to Tenet later Tuesday.

The competing security forces have created fierce rivalries among the various security chiefs, and some will inevitably lose out if Arafat slashes the number of senior posts.

The United States and European nations have contributed millions of dollars to the Palestinian security forces, and are expected to give millions more. But they are also expected to monitor closely how the Palestinians go about overhauling the security forces.

The White House, meanwhile, announced Monday that Sharon would meet with President Bush next week in a hastily arranged gettogether in Washington. Next Monday will be the sixth time the two men have met.

Tenet, on a six-nation Mideast tour to gauge Arab support for changes in the Palestinian Authority, will be seeking details when he holds talks with Arafat.

Palestinian sources said Arafat is likely to remain in overall charge of the restructured security forces.

Despite his pledge to make changes, Arafat faces a diverse group of critics. They include many Palestinians, who are highly critical of corruption in their government; the United States, which wants to see greater democracy, and the Israelis, whose top priority is a halt to the attacks.

The militant Islamic group Hamas, meanwhile, rejected Arafat's offer to join a new, more compact Palestinian Cabinet that's been under discussion and will be announced in the coming days.

Arafat has offered Cabinet posts to four militant groups that have been involved in attacks against Israel, including homicide bombings. All have now rejected the proposal.

Of the more than 60 homicide attacks by Palestinians in the current Mideast conflict, Hamas' military wing has carried out more than any other group, including the deadliest attacks. The group has rejected Arafat's call to halt them.