Lawyers for the Prince George's County NAACP have told a federal court judge that the county school board should be required to develop a plan to bring the schools within guidelines for racial balance by Sept. 1.

The comments came in a letter filed Friday with District Court Judge Frank A. Kaufman in Baltimore following that judge's recent decision that some schools in Prince George's remain racially segregated.

In his June ruling on a suit charging that the schools discriminated against black students, Kaufman found the educational practices of the schools to be racially fair. In that decision, Kaufman said tentatively that no school should have an enrollment of less than 10 percent or more than 80 percent black.

Hearings on what remedy should be applied for schools falling outside of those guidelines will be scheduled for this fall, according to lawyers in the case.

In their letter the NAACP lawyers, from the firm of Hogan and Hartson, also told the judge that the racial guidelines should call for enrollments within 20 percentage points of the black population in the school system, which is currently 55 percent black. If officials cannot bring some schools into racial balance, the attorneys said, "it would be useful and appropriate" for the system to apply "special compensatory educational resources," such as teachers or additional spending, "to help minority students overcome the consequences of a virtually one-race school."