The federal government has put new muscle into its fight with Arlington developers over the construction of high-rise buildings that are visible from the Mall and downtown Washington.

A top official in the Department of Housing and Urban Development said yesterday that he expects Hud to withhold federal mortgage insurance and subsidy funds from a proposed Crystal City high-rise apartment project unless the developer reduces its proposed 24-story height.

Earlier yesterday the National Capital Planning Commission -- the federal planning agency for the Washington area -- voted unaimously to urge HUD not to approve federal support for the project because the building would "intrude visually . . . on the monumental core of the Nation's capital."

The planning commission is urging a reduction of 53 feet, or five stories, in the proposed 24-story Breakenridge Apartments at 1211 S. Eads St. near the Pentagon City Metro subway station. If approved, the change would make the building almost invisible from downtown washington.

Elliot Bernold, regional director of housing for HUD, said after yesterday's meeting that his agency "will ask the [developer] to reduce the building height" before federal support for it will be approved.

The developer -- Palmer, Franc, Green and King Ltd. -- could not be reached for comment. Bernold said the firm has requested mortagage insurance for the project and federal rent subsidy funds for 20 percent of the proposed 374 one- and two-bedroom apartments.

Until yesterday, the federal planning commission had unsuccessfully attempted to block construction -- or at least lower the height -- of at least six Arlington skyscrapers. It now is urging the county not to approve construction of a 14-story office building opposite the county courthouse, and to refuse to rezone land around subway stations to allow construction of buildings as high as 24 stories.

The federal planning agency and the Department of Interior lost a lawsuit against Arlington last fall, when they sought to block construction of four Rosslyn buildings, once as high as 29 stories, that the county had approved for a Virginia bluff overlooking Georgetown and the Potomac.

The county has a maximum height limit for buildings of 16 stories for hotels and apartment buildings, and 12 stories for offices, but regularly waives the height restrictions in exchange for "bonus provisions" -- which Arlington officials say include considerations such as "significant public contributions" by developers.

County officials have spurned federal requests to keep buildings low -- and thus invisible from the Mall -- as federal "meddling" in local matters.

"This is just the latest NCPC tactic," Arlington's chief of current planning, Hal Glidden, said yesterday. "They've been trying to limit heights all over Arlington. It's been tested in the courts and they lost and I guess you could say that now we've just agreed to disagree."

Glidden said another tactic will be "to try to link their height limitations" to the federal government's leasing practices. The General Services Administration leases space for 24,000 federal employes in Arlington, mostly in Rossyln and Crystal City, the areas where the height controversy has arisen.

The federal planning agency next month expected to adopt one segment of a comprehensive plan for the entire Washington area that will call for specific height limits around Washington's "topographic bowl," the ridge of hills that circles most of the city.

While the plan will be only advisory, and can be ignored by suburban jurisdictions like Arlington, the planning commission is likely to recommend that all federal agencies support it.

It GSA refuses to lease or renew leases in high-rise buildings considered to "ruin" the Washingotn skyline, then the planners say there will be little incentive for developers to build them. Many of the controversial high-rise office buildings were built specifically to house federal agencies, although the practice of leasing privately owned office space here has been curtailed by Congress.

Planning Commission Chairman David Childs is to meet with the Arlington County Board later this month to discuss the proposed plan and its height restrictions. The date of the meeting is expected to be set Sept. 13, when the board is expected to approve yet another high-rise project opposed by the federal planners -- a 14-story office building opposite the Arlington county courthouse.

The federal planners yesterday unanimously urged the county board and its planning commission not to approve any building higher than 60 feet, or six stories, in the courthouse area because it is on the ridge overlooking Washington.