President Bush is calling on all nations to cut off terrorist financing to stop violence in the Middle East. The president is responding to Wednesday's bus bombing in downtown Jerusalem and the Israeli helicopter strike that followed.

President Bush strongly condemns the bus bombing and calls on all nations to not only denounce the violence but use what he calls "every ounce of their power" to prevent it from happening again.

"For the people in the world who want to see peace in the Middle East, I strongly urge all of you to fight off terror, to cut off money to organizations such as Hamas, to isolate those who hate so much that they are willing to kill to stop peace from going forward," the president said.

The Palestinian militant group Hamas has claimed responsibility for Wednesday's bombing which followed an Israeli attempt Tuesday to assassinate a top Hamas official.

The violence threatens the so-called "road map" for Middle East peace less than a week after the president met with Israeli and Palestinian leaders to push the power-sharing deal.

Bush administration officials acknowledged that plan would have to overcome some violent opposition. But the speed of this week's cycle of violence has come sooner than the White House anticipated, even before the arrival of a new U.S. coordinator to implement some of the plan's early stages.

The president had hoped that new Palestinian Prime Minister Mahmoud Abbas would have some time to build up a force to challenge Hamas. Mr. Bush criticized Israel's Tuesday assassination attempt for undermining Palestinian efforts to fight terrorism and doing nothing to improve Israeli security.

Speaking to reporters in the Midwest city of Chicago Wednesday, Mr. Bush condemned those trying to disrupt the peace plan with violence.

"It is clear there are people in the Middle East who hate peace," he said. "There are people who want to kill in order to make sure that the desires of Israel to live secure in peace don't happen, who kill to make sure the desires of the prime minister of the Palestinian Authority and others of a peaceful state living side by side with Israel do not happen."

Bush administration officials are continuing wide-ranging telephone diplomacy with Israeli and Palestinian officials to try and maintain momentum for the peace plan in the face of continuing violence.