Updated

The Pentagon is designing a missile defense test program that would allow some of its elements, such as ground-based interceptors or airborne lasers, to be used in combat within a few years.

Bush administration officials said this would be done only in a national emergency such as a threat of missile attack from North Korea.

Pentagon officials, explaining the approach Thursday in testimony before the Senate Armed Services Committee, made clear that they intend to accelerate work on a deployable missile defense even at the cost of withdrawing from the 1972 Anti-Ballistic Missile Treaty banning national missile defenses.

The administration has set no date for deploying a defensive barrier against long-range ballistic missiles.

The officials encountered sharp questioning from some Democrats, including the committee's chairman, Sen. Carl Levin of Michigan, who declared themselves unwilling to support the administration's request for $8.3 billion for missile defense research and testing in 2002. That would be a 57 percent increase over this year's allocation.

Levin criticized Deputy Defense Secretary Paul Wolfowitz for failing to clarify for Congress whether missile defense tests planned for the budget year starting Oct. 1 would violate the ABM Treaty.

``I've yet to receive an answer,'' Levin told Wolfowitz. In his testimony, Wolfowitz said missile defense tests will ``bump up against'' treaty restrictions, and this probably will occur ``in months rather than in years.''