The chairman of a federal commission considering a plan to move 23,000 defense workers out of leased buildings in Northern Virginia for security reasons said yesterday that the panel had no "bias" against rented buildings, which he said could be safe workplaces.

The remarks by Anthony J. Principi, chairman of the Base Realignment and Closure Commission, did not exclude the possibility of huge shifts of military personnel across the region under a Pentagon proposal.

But Sen. John W. Warner (R-Va.) and Reps. James P. Moran Jr. (D-Va.) and Thomas M. Davis III (R-Va.) described Principi's comments as the clearest sign that a months-long campaign by state and local officials over the legality and value of shifting thousands of skilled military workers into new buildings on closed military bases is having an impact.

Principi's statements came at the last of more than 20 hearings into a nationwide streamlining plan proposed May 13 by Defense Secretary Donald H. Rumsfeld. The plan calls for shuttering facilities to save $49 billion over 20 years.

Arlington and Fairfax counties and the city of Alexandria would be among the hardest-hit areas in the country, losing jobs at dozens of leased sites.

In Washington, nearly 6,000 jobs would move from Walter Reed Army Medical Center to a renamed Walter Reed National Military Medical Center in Bethesda and to Fort Belvoir in southeastern Fairfax.

Beyond the Capital Beltway, Maryland and Virginia would gain more than 20,000 jobs at such federally owned bases as Belvoir, Fort Meade and Aberdeen Proving Ground.

Yesterday, Principi raised the issue of leased space while defending the panel's proposal to create a Joint Medical Command Headquarters by bringing together 1,300 Navy, Air Force and Army personnel who are split between the District and Northern Virginia.

Virginia and District leaders opposed that idea, which they said would move District-based Navy and Air Force medical offices and Virginia-based Army offices to Bethesda. D.C. Del. Eleanor Holmes Norton (D) said Bolling Air Force Base in the District should be considered.

Principi said no site for a headquarters has been proposed. All commands might join Army personnel at the leased Skyline Towers complex in Falls Church, he said.

"We have not said . . . that we need to move people out of leased space," Principi said. "It may be most appropriate to move people into leased space in Northern Virginia, close to the Pentagon."

A few minutes later, Principi distanced himself more broadly from the Pentagon's position that operations be dispersed from Washington and that workers be moved from leased buildings that fail to meet new security standards -- including at least an 82-foot buffer from surrounding traffic to defend against truck bombs. Almost all leased buildings in metropolitan Washington and several major U.S. cities lack such setbacks.

"That bias is not on the part of the commission," Principi said. "That's the recommendation of the Defense Department, not the commission."

Speaking to reporters after the day-long hearing, Principi said commissioners strongly supported Pentagon moves to protect military and civilian defense workers from terrorist and other attacks, but he suggested that leased buildings could be secure.

"We saw what happened in Oklahoma City," Principi said, referring to the 1995 bombing of the Alfred P. Murrah Federal Building that killed 168 people. "We want to be sure when we house civilian employees in this day and age, in a war on terrorism, that they're in safe locations. That could be in a leased facility, and that could be behind a fence" on a base, he said.

Virginia officials welcomed Principi's remarks.

"It's very encouraging," said Davis, who testified yesterday along with Moran and Fairfax Board of Supervisors Chairman Gerald E. Connolly (D). "It's the first time we've heard that definitively from the commission."

Warner, chairman of the Senate Armed Services Committee, was more cautious. He said officials would continue to argue that the commission would violate the law if it fast-tracked closures of rented facilities for security reasons, instead of leaving leasing decisions to the defense secretary, as is the norm.

"I sleep with one eye open until this thing is finished," said Warner, who helped write the law guiding five rounds of national base closings and whose office has submitted legal briefs outlining a potential challenge to the commission's actions.

The commission will begin drafting the final list of base closures Aug. 24 and present it to President Bush Sept. 8. The president and Congress must accept or reject the list in full.