PRAGUE, Czech Republic - Fighting global terror has replaced Cold War deterrence as NATO's core mission, President Bush said yesterday in urging European allies to "come with us" to help disarm Iraq.

Bush's comments came as he prepared to meet with NATO leaders during the next several days. Behind the scenes, he is expected to try gaining coalition backing for possible military action against Baghdad.

A decade after the collapse of the Soviet Union, the trans-Atlantic alliance that once stood sentry against Russian aggression must remake itself to help defeat the followers of Osama bin Laden and similar terrorist groups, Bush said.

"That's the biggest threat to freedom right now," Bush said in a Czech TV interview that the White House released yesterday, just as the president arrived in this scenic Central European capital aboard Air Force One.

Security was extraordinarily tight. The Czech government mobilized 12,000 police officers and several thousand more soldiers and specially trained anti-terrorist forces. U.S. warplanes helped patrol airspace.

"We face new threats, and the new threats are global terror," Bush said in the interview. "One way to make sure NATO is relevant is to focus on the true threats to freedom, address those threats and figure out ways that we can work together."

NATO is embarked on a drive to restructure its might, moving away from the rusting heavy tank and artillery divisions built up to deter a Soviet campaign across the plains of Germany and toward a lighter, more flexible and transportable force.

Also, in a move that will push NATO hundreds of miles beyond the old Iron Curtain, Bush and his counterparts from the 19-nation alliance are expected to admit seven new members - Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia and Slovenia - at a formal NATO summit session here tomorrow.

"NATO used to be a way to defend Europe from the Warsaw Pact," Bush said, referring to the old Soviet alliance extending from the Baltics to the edge of Western Europe. "But the Warsaw Pact no longer exists. Russia is not an enemy."

In calling the alliance to a wholly new mission to replace its old charge, Bush aims to press for further changes aimed at strengthening NATO's ability to intercept, disrupt and destroy terrorist cells around the world.

He also wants a 21,000-strong rapid response team made up of NATO forces, capable of deploying on short notice to fight intensive combat anywhere in the world.

Bush, who has said the need for assertive action against Iraq is part of his broader anti-terror campaign, plans to press his NATO allies behind the scenes to sign on to what he called "a coalition of the willing" for a possible military showdown with Iraq.

If he orders the United States to attack Iraq, Bush said, "Of course, I hope our NATO friends come with us."