Two buses and a van carrying inmates to the D.C. Jail in Southeast Washington were prevented from entering the facility for nearly three hours last night because their presence would have forced the jail over its court-imposed inmate population ceiling.

The inmates, including 48 who went there from D.C. Superior Court, were finally admitted to the jail about 9 p.m., after corrections officials moved a similar number of inmates out of the jail and into other institutions.

But federal officials said 36 of the 48 inmates on the buses were simply being returned to the jail after appearances in court and should have been expected by jail officials.

Corrections Director James F. Palmer conceded in an interview that "vacancies" at Lorton Reformatory, into which some of the jail inmates were being moved last night, wouldn't open until other prisoners were released today.

"I'm putting people on vacancies that will occur tomorrow," he said, pointing out that tomorrow begins at midnight. "I'm stretching the system to try to get my system a day or two ahead."

City Administrator Thomas Downs vowed that the city would not violate the inmate cap. "We will not create a crisis," he said. "We will demonstrate we have exercised every reasonable and responsible option available to the government."

He said one of the options is to put more inmates into the Special Temporary Employment Program, which was created to help ease the prison system's crowding problem by providing city jobs to inmates who meet other conditions for parole.

Police sources said yesterday that inmates working under the program at the 4th Police District may have compromised sensitive police operations.

Law enforcement officials said that busloads of prisoners have had to wait for admittance to the jail each of the last three days as corrections officials carried out almost continuous movements of inmates in an effort to remain under the 1,694 ceiling set Aug. 22 by U.S. District Judge William B. Bryant.

On Sunday the official 4 a.m. count at the jail reached 1,691 and yesterday the early morning tally was 1,690.

Palmer said last night that as long as the incoming inmates remained on the buses -- even though some were inside the jail's perimeter fence -- they would not have to be counted in the jail's overall population.

"They're not going anywhere," Palmer said of the inmates who sat in the vehicles for hours. "We have plenty of security on them."

Palmer projected that the jail population for the 4 a.m. count today would be 1,683 to 1,690.

In a related matter, attorneys for inmates at Lorton Reformatory's Central facility asked a federal district judge yesterday to hold the city in contempt for violating her court order governing operations of the prison and to appoint a "special master" to monitor the city's compliance.

The attorneys, citing what they described as nearly three years of city noncompliance, asked U.S. District Judge June Green to fine the city $7,500 and order it to pay the attorneys' legal fees.

Attorneys for jail inmates have asked Judge Bryant to hold the city in contempt and fine it $50,000 for violating the inmate cap on Dec. 7 and then trying to cover up the violation.

In addition, the city has asked that the federal government be made a defendant in the 15-year-old suit that resulted in the imposition of the inmate ceiling, contending that the attorney general ultimately has custody over D.C. prisoners.

But at a hearing last month, Bryant -- who has not ruled on the contempt motion -- told the city that providing prison space for D.C. prisoners is the responsibility of the city.

D.C. officials blame many of their current crowding problems on a Jan. 14 decision by Deputy Attorney General D. Lowell Jensen to end a 4 1/2-month-old agreement under which newly sentenced D.C. prisoners were sent to federal institutions. Jensen said in a letter to Mayor Marion Barry that he ended the agreement because the city was not proceeding with plans to build a new prison inside the District.

Although city officials repeatedly have asked the government to resume taking prisoners, Jensen told Barry that the request would not be considered until the city has made "some movement" on providing a temporary facility to ease crowding.

Palmer said 63 new inmates from Superior Court were placed in the custody of the corrections department yesterday. To help make room at the jail for them, Palmer said, he expected to move 26 other inmates to various facilities at Lorton, in southern Fairfax County.

The director said that 37 additional spaces in the corrections system were to be freed by the release of a like number of inmates from various institutions, including the jail. He said they were being released because they had completed their sentences or were being sent to halfway houses.

The three city-operated halfway houses are already far above capacity, according to the Corrections Department's figures.

For example, at the Community Center 1 at 1010 North Capitol St., which has a capacity of 125, a total of 203 persons were being housed yesterday. Community Center 3 at 1430 G St. NE, with a capacity of 45, had 86 persons.

It was unclear last night if a job action taken Tuesday by 17 of 26 medical personnel at the jail had affected how quickly the city was able to move prisoners. Under the court order, all newly admitted jail inmates are required to have a physical examination within 24 hours of their arrival.

Corrections spokesman LeRoy Anderson said that 12 of the 17 medical employes at the jail who did not report for work on Tuesday have been placed on administrative leave pending their termination.