(AP) - President Bush, who once expressed disdain for the United Nations, said Tuesday that multinational organizations are now "needed more urgently than ever" to combat terrorists and extremists who are threatening world order.

In his eighth and final speech to the U.N. General Assembly,Bush said the international community must stand firm against thenuclear ambitions of North Korea and Iran. He scolded Russia forinvading neighboring Georgia. And he said that despite pastdisagreements over the U.S.-led war in Iraq, members of the U.N.must unite to help the struggling democracy succeed.

"A few nations, regimes like Syria and Iran, continue tosponsor terror," Bush said. "Yet their numbers are growing fewer,and they're growing more isolated from the world. As the 21stcentury unfolds, some may be tempted to assume that the threat hasreceded. This would be comforting. It would be wrong. Theterrorists believe time is on their side, so they've made waitingout civilized nations part of their strategy. We must not allowthem to succeed."

Bush said that instead of issuing statements and resolutionsafter terrorist attacks, the U.N. and such organizations must workclosely to prevent violence. Every nation has responsibilities toprevent its territory from being used for terrorist, drugtrafficking and nuclear proliferation.

Bush, who ordered the U.S.-led invasion of Iraq without theU.N.'s blessing, said: "The United Nations and other multilateralorganizations are needed more urgently than ever."

His appearance was overshadowed by the U.S. financial marketscrisis that has rippled through world markets. Trying to reassureworld leaders that his administration is taking decisive action tostem market turmoil, Bush said he is confident that Congress willact in the "urgent time frame required" to prevent broaderproblem. But he did not ask other nations to take any specificactions.Click here for excerpts of President Bush's speech