ISRAEL HEMS IN WEST BANK.

Byline: Serge Schmemann The New York Times

Israeli troops fanned out across the West Bank on Tuesday, welding shut houses and barricading Palestinians in their towns and villages in retaliation for four attacks within nine days by suicide bombers.

As the new Israeli crackdown got under way, the political and military wings of Hamas again declared a three-month cease-fire. But after two earlier such announcements, both followed by new bombings, the latest communiques only bolstered suspicions that Hamas was divided into separate factions not controlled by any central authority.

It was also not clear whether the latest attack, an explosion outside a Tel Aviv mall Monday that took 13 lives, was the work of Hamas. An anonymous caller to Israel Radio's Arabic service, who purported to be calling in the name of Hamas, said the attack was carried out by Islamic Jihad, a small group based in Syria dedicated to attacks on Israel.

In any case, after four consecutive bombings in which 61 died, including the bombers, Israel was in no mood to listen to offers of cease-fire, which looked increasingly like efforts to forestall retribution.

Prime Minister Shimon Peres, paying a visit to the Lebanese border, where four Israeli soldiers were killed by a land mine Monday, said the measures in the West Bank were only the beginning. "They had their say," he said. "They'll get a response."

Among the first houses sealed off at dawn, in a village north of the West Bank city of Nablus, belonged to the family of Yahya Ayyash, the bomb-maker known as "the Engineer" in whose name the first three bombers struck. Ayyash was assassinated Jan. 5 in Gaza.

Israel Radio said eight other homes were sealed with metal plates, and Israeli soldiers also fanned out across the West Bank to cordon off villages and towns, preventing any movement of Palestinians even among their own settlements. About 150 purported supporters of the Islamic movement Hamas were reportedly rounded up by the Israeli forces.

Commentators across the political spectrum spoke of Israel as a country once again at war and echoed the public's cry for action.

Nahum Barnea, a popular liberal columnist for Yediot Ahronot, whose own son, Sgt. Yonatan Barnea, was killed in the first bus bombing Jan. 25, wrote on Tuesday: "The first attack in the series was a terrible blow. The second was catastrophic. The third creates a reality which must be confronted."

Ofer Shelah of Maariv, a conservative daily, wrote: "We don't care any more what they will do, the main thing is to do something." In the mood of desperate anger, there was no way to tell which way the future would tilt. If Peres was perceived as not having done enough, or if there were yet more attacks, he stood to lose much support.

Already on Monday, leaks from within the government spoke of the possibility of bringing the conservative Likud party into a government of national unity, or of Peres relinquishing the Ministry of Defense to Foreign Minister Ehud Barak, a former Army chief of staff. So strong were the rumors, that Peres sent a spokesman out during the meeting to deny them.

CAPTION(S):

A teen-ager at Tel Mond cemetery mourns three of her friends who were killed in Monday's suicide bombing of a Tel Aviv mall. Associated Press