The National Park Service wants to demolish a modernistic visitor center on one of the most significant sites of the Gettysburg battlefield, but an architectural preservation group is suing because the building itself is historically important.

The lawsuit filed Wednesday in a Washington D.C. federal court is the latest escalation in a long-standing dispute over the fate of the Cyclorama Building. Built in 1958 by famed modernist architect Richard Neutra, the visitor center is named for the large, circular painting of the famous Civil War battle.

Its construction was part of a massive nationwide park modernization plan, and the building is eligible for registration as a national historical landmark.

It was built, however, near one the highest points on Cemetery Ridge, a key defensive position where nearly 1,000 Union soldiers were killed or wounded during Pickett's Charge.

The Advisory Council on Historic Preservation said in 1999 the battlefield's significance trumped that of the building and recommended tearing it down. Park officials plan to open a new museum and visitor center in 2008.

The lawsuit, filed by the Virginia-based Recent Past Preservation Network and Neutra's son, argues the government is violating federal preservation laws. The lawsuit claims the Park Service did not adequately study the effect of the demolition or consider other uses for the building.

The Park Service had no comment Wednesday. A description of the plans on the service's Web site, however, says the new visitor center will be located alongside the battlefield in a low-lying area that saw no major battle action.

The Cyclorama painting will be moved to the new museum.

The preservation group said in its lawsuit that it does not oppose the plan to restore the battlefield and would not object if the building was moved off the park.