The 4th U.S. Circuit Court of Appeals dealt a blow to the Prince George's County Board of Education yesterday by upholding a lower court's order to desegregate county schools, citing statistics that showed schools became more segregated during the 1970s.

School officials yesterday would not say whether they will appeal the case to the U.S. Supreme Court.

The school board had filed an appeal of U.S. District Court Judge Frank A. Kaufman's 1983 ruling that Prince George's County should desegregate its school system, which, with 105,000 students, is now the Washington area's second largest.

While the appeal was being pursued, Kaufman had taken steps toward implementing his ruling. He appointed a panel of experts to recommend how the school system should desegregate, and the panel recently produced a report calling for extensive busing and school closings. School officials must file their response to the panel's recommendations by April 22, and Kaufman will rule sometime after that on the final shape of the desegregation plans.

The county NAACP, which filed the desegregation suit against the board in 1972, claimed complete victory in the appellate court's opinion.

"We're delighted with the court's decision," said Joseph M. Hassett, attorney for the civil rights organization. "The clear message of the court is that the school board has run out of excuses and it's time for them to discharge their duty in desegregating Prince George's County schools."

The appeals court went so far as to send back to Kaufman one area in which he had ruled in favor of the school board. The issue -- whether the schools were discriminatory in assigning black students to special education classes and programs for gifted children -- was returned because, the appeals panel said, the burden of proof should have been placed on the school board rather than on the NAACP.

School officials yesterday pointed to the appellate court's ruling that Kaufman was correct in finding no intentional discrimination against black students.

"We are certainly pleased that the appeals court affirmed the finding of no intentional discrimination," said school spokesman Brian J. Porter. "It lends credence to our argument that the changes in school enrollments are the result of significant demographic changes and not actions by the school board."

Hassett, however, said the question of discriminatory intent is "a non-issue."

In a series of court battles, the NAACP has contended that the board has discriminated against black students, while school officials have argued that racial imbalance in their system has been caused by demographic changes rather than discrimination.

In 1983, Kaufman ordered the board to take steps to bring school enrollment within guidelines of no more than 80 percent and no less than 10 percent black.

The school board appealed that ruling, arguing that in 1975 Kaufman relinquished jurisdiction over the schools when he said that a desgregation plan already in place "was meeting constitutional obligations." Given that, the board argued it should not be required to continuously adjust its busing plans in response to population shifts.

The appeals court, however, ruled that Kaufman acted properly in exercising his jurisdiction over the county's desegregation efforts because the school system had never been fully integrated. "Until a unitary system is created, a school system is not absolved from this duty to eliminate segregation by reason of demographic changes," the court said.

The appeals court cited statistics showing that schools with predominantly black enrollment in 1972 had even higher black enrollment a decade later. "Their identities as black schools had never been eradicated," the court concluded. Also, more schools were "in imminent danger of tipping and joining the ranks" of these predominantly black schools, the court found, and the board's "unilateral cancellation of portions of the busing plan exacerbated the problem."

On another issue, the appeals court agreed with the NAACP, which filed a cross-appeal, that Kaufman had erred in forcing the NAACP to prove that discrimination had led to disparities in the placement of black children in certain programs. The NAACP had argued that the disproportionately high numbers of black students in special education programs, and disproportionately low numbers in classes for gifted children was "causally related to pre-1973 segregation."

The appeals panel consisted of Chief Judge Harrison L. Winter, of Baltimore, and judges Francis D. Murnaghan, also of Baltimore, and J. Dickson Phillips Jr., of North Carolina.