The cell block in D.C. Superior Court building B, where the District houses inmates sentenced to spend the weekend in jail, had 67 prisoners Friday night -- three more than court officials had been told would be kept there, a Corrections Department source said yesterday.

The source, who asked not to be identified, said that the three inmates spent the night in bunks in a hallway near toilets in the cell block and that three more "weekenders" were expected at the facility last night, which would bring to 70 the number incarcerated there.

The long-vacant cell block was refurbished by the city in late March to accommodate weekend-only prisoners. Previously they had been housed in a dormitory at Lorton Reformatory, which was converted for use by long-term inmates.

Before being transported to Lorton, the weekenders had to be processed through the D.C. Jail, where they have occasionally been held on buses for as long as 10 hours because their presence inside would have put the jail over a court-imposed limit of 1,694 inmates.

When the city received permission to use the cell block from the Joint Committee on Judicial Administration, the committee was assured that no more than 64 persons Three inmates spent Friday night in a hallway. would be housed there, according to Larry P. Polansky, executive officer for the court.

"There is a hard-and-fast rule, and there was an agreement between the court and the District government as to how many people is the maximum number allowed at the cell block," D.C. Court of Appeals Chief Judge William C. Pryor, chairman of the committee, said yesterday.

City officials could not be reached for comment.