"The United States will take every necessary measure to protect our citizens against what is perhaps the greatest danger of all: The catastrophic harm that may result from hostile states or terrorist groups armed with weapons of mass destruction and the means to deliver them," he said in a statement read by spokesman Ari Fleischer.

Earlier, administration officials said Bush and Defense Secretary Donald Rumsfeld would detail plans to deploy 10 ground-based interceptor missiles at Fort Greeley, Alaska, by 2004 and an additional 10 interceptors by 2005 or

"While modest, these capabilities will add to America's security and serve as a starting point for improved and expanded capabilities later as further progress is made in researching and developing missile defense technologies and in light of changes in the threat," said Bush.

Bush gave the controversial program -- which has drawn fire from Russia and China -- the green light despite the failure of a test missile to hit an incoming dummy long-range missile in a test last week.

"When I came to office, I made the commitment to transform America's national security strategy and defense capabilities to meet the threats of the 21st Century," the president said.

"Today, I am pleased to announce that we will take another important step in countering these threats by beginning to field missile defense capabilities to protect the United States as well as our friends and allies," he said.

SPACE.WIRE