Updated

A carefully worded, almost skeptical reaction came from the White House Thursday to Palestinian leader Yasser Arafat's announcement that he will immediately begin implementing a cease-fire and start neutralizing Palestinian terrorists.

National Security Council spokesman Sean McCormack told Fox News: "We've heard what Chairman Arafat has said. We are examining what he said. We are looking at his words."

McCormack added: "Our diplomatic people are in touch with Palestinian Authority representatives. Our diplomats are in constant contact with the State Department."

Early Friday, Israel's Cabinet declared Arafat an "enemy" and Israeli troops entered his West Bank compound in Ramallah, exchanging fire with his personal guard.

Referring to the U.S. truce effort, Israeli Prime Minister Ariel Sharon said Israel was prepared to do everything it could for a cease-fire, "but all Israel got in return was terrorism, terrorism and more terrorism."

President Bush himself has not been heard from since Arafat's Thursday announcement. In it, Arafat said he was willing to work toward peace in concert with U.S. Special Envoy Gen. Anthony Zinni — who has been in the region for more than a week negotiating a plan to end violence in accordance with the plan proposed by CIA Director George Tenet — and move toward a negotiated land settlement and recognition of a Palestinian state foreseen in the Mitchell plan named after former Maine Sen. George Mitchell.

"I would like to work for an immediate cease-fire," Arafat said. "I have notified Gen. Anthony Zinni and on this occasion I would like to express my deepest appreciation for the maximum efforts he's exerting. We informed him that we are ready ... to immediately begin implementation of the Tenet peace plan without any conditions ... and without prejudicing any of its articles. Also, we have notified him of our readiness to defend and report accommodations."

Arafat did not say that Palestinians would lay down their weapons, a central component of the Tenet plan.

At a fundraiser for Texas Senate candidate John Cornyn, the president said that despite Wednesday's Passover massacre that killed 20 and injured 130 Israelis sitting down for a Passover seder at a hotel in northern Israel, his administration is not "giving up" on its efforts to broker a cease-fire between the Israelis and the Palestinians.

"We're not going to let murderers disrupt the march to peace. My heart breaks for those who were celebrating Passover in a hotel when a cold-blooded killer came in and destroyed innocent life, to derail the attempts of peace-loving people for coming together. But they're not going to stop us as a nation longing for peace and working for peace," Bush said.

The White House acknowledges that Arafat has so far failed to abide by a March 19 promise to Zinni that he would immediately begin implementing the Tenet plan.

If that did not happen within a week's time, Vice President Dick Cheney, who announced the commitment, said it would "torpedo" the U.S. peace initiative.