WASHINGTON (AP) _ The White House on Monday called for ``clear and unambiguous'' condemnations of the school bus attack that killed two Israeli teachers, wounded five children and prompted Israel to fire rockets on Gaza City in retaliation

U.S. officials were urging the Palestinian Authority to move quickly to arrest suspects in the bombing and halt the cycle of retribution sustaining the violence, said national security spokesman P.J. Crowley.

In turn, Israel was being urged to refrain from ``the use of excessive force in response'' to such incidents, Crowley said. But U.S. officials carefully avoided cautioning Israel against less forceful reactions, particularly if it turns out that radical militants were responsible for the bus attack.

``Obviously we condemn the attack against innocent civilians,'' Crowley said. ``But we are also concerned about excessive force in response that only fuels the current cycle of violence that both sides need to break.''

In Washington, Secretary of State Madeleine Albright offered condolences to the victims' families and called for ``restraint by all sides.'' ``Violence cannot solve security problems'' in the region, she said, without elaboration.

State Department spokesman Richard Boucher said the United States expects the Palestinian Authority to condemn it and take quick action toward restoring calm. As for Israel, ``Israelis need to understand excessive use of force is not the way,'' Boucher said.

Israelis and Palestinians have waged attacks and counterattacks for more than two months, killing more than 230 people, mainly Palestinians. Leaders on both sides have tried over the past few days to reduce the violence, Crowley said, ``and now, this tragic attack puts all of this at risk.''

``Every time there is loss of life, we seem to continue the cycle of violence with an action and reaction that does not serve the interest of either side,'' Crowley said. ``That's why there needs to be clear and unambiguous calls from the leadership that this violence has to stop.''