In advance of the departure to the Middle East of U.S. peace envoy Anthony Zinni, the State Department aimed sharp criticism at both Israel and the Palestinians for the wave of violence in the region. Secretary of State Colin Powell telephoned Israeli Prime Minister Ariel Sharon and Palestinian leader Yasser Arafat Friday to underscore U.S. concern.

Officials here are watching the mounting violence with dismay, as it makes Mr. Zinni's quest for implementation of last year's cease-fire plan of CIA Director George Tenet all the more difficult.

Briefing reporters, State Department spokesman Richard Boucher said "heinous" acts of terror by Palestinians such as Thursday's gun attack on schoolboys at a Jewish settlement in Gaza can only harm the interests of the Palestinian people.

But he also said Israeli Prime Minister Ariel Sharon should re-think his strategy of military reprisals.

"Prime Minister Sharon has to take a hard look at his policies to see whether they will work. Declaring war against the Palestinians and attempting to solve the problem through military action doesn't lead us anywhere," said Mr. Boucher. "Right now both sides should think through the consequences of the policies they're following. Both parties need to take a hard look at what they're doing now, and take the necessary steps so that they can implement the Tenet work plan immediately, as a first step toward full implementation of the Mitchell committee recommendations."

Spokesman Boucher said U.S. officials are "very concerned" about recurring reports that Israeli forces whether deliberately or not have attacked Palestinian ambulances, medical personnel, and others trying to cross checkpoints for emergency reasons.

He said it is "imperative" that Israeli forces exercise "utmost restraint and discipline" to avoid further harm to civilians.

The spokesman also said the administration is "deeply troubled" by reports of vigilante action by Jewish settlers against Palestinian villagers in the West Bank near Nablus.

The Tenet plan, hammered out by the CIA chief on a Middle East shuttle mission last June, was never officially published.

But leaked texts carried by Israeli newspapers say it provides for, among other things, the resumption of Israeli-Palestinian security cooperation, the apprehension of Palestinian terrorists, an end to Israeli attacks on Palestinian Authority facilities, and a redeployment of Israeli forces away from Palestinian cities.

Spokesman Boucher said the administration hopes to see steps toward its implementation even before Mr. Zinni's expected arrival in the area the middle of next week.

That is understood to have been one of the points made by Secretary of State Powell in his Friday telephone calls to Mr. Arafat and Prime Minister Sharon.