Bush visited a Boeing military equipment factory in this northeastern city and noted that the company had installed "the first ballistic missile interceptor into its silo at Fort Greely, Alaska."

"It's the beginning of a missile defense system that was envisioned by (the late former president) Ronald Reagan, a system necessary to protect us against the threats of the 21st century," Bush said.

"We want to continue to perfect this system, so we say to those tyrants who believe they can blackmail America and the free world: 'You fire, we're going to shoot it down'," he said.

"I think those who oppose this ballistic missile system really don't understand the threats of the 21st century. They're living in the past. We're living in the future. We're going to do what's necessary to protect this country."

The Republican president did not mention Massachusetts Senator John Kerry, his Democratic opponent in the November 2 election. Kerry has not taken a position on the missile shield, but he has indicated that he would cut the military budget to slash the federal deficit.

The anti-missile system is among Bush's priorities. The administration insists that even an imperfect system could dissuade other nations from developing long-range missiles.

The Pentagon plans to deploy some 10 missile interceptors in Alaska and California this year. Bush has approved 10 billion dollars for the project in the 2005 defense budget, which totals 400 billion dollars.

WAR.WIRE