The U.S. Justice Department said yesterday it has established a special permanent task force to investigate all criminal activity at the District's Lorton Reformatory, beginning with Thursday's daylong uprising that left more than 30 persons injured and a half-dozen prison buildings in smoking ruins.

"In our view, the time has come to wrest control from the prisoners at Lorton and place it back into the hands of law enforcement officials," said Henry E. Hudson, U.S. attorney for eastern Virginia, at a joint news conference with Joseph E. diGenova, U.S. attorney for the District of Columbia.

Officials said that formation of the task force is unprecedented, noting that most previous federal investigations have been limited to specific incidents rather than wide-ranging probes conducted by prosecutors assigned solely to those matters.

But at his own news conference later in the day, Mayor Marion Barry, whose management of city prisons came under attack by Hudson and diGenova, characterized the investigation as routine because the prison is on federal land and federal authorities have jurisdiction there. Barry pointedly avoided criticisms of federal officials but used the conference to report that the city was in "total" control of its prison problems.

While strongly criticizing what diGenova described as years of mismanagement at Lorton, the prosecutors said the federal government does not intend to "take control" of the prison complex. "We just want more discipline in the institution is the bottom line," Hudson said.

The federal task force will be composed of prosecutors from Hudson's and diGenova's offices and the Justice Department. Providing backup for the prosecutors will be FBI agents from the Alexandria field office and deputy U.S. marshals. Joseph A. Krahling, head of the Alexandria FBI office, said his agents have already conducted "hundreds of interviews" since Thursday.

DiGenova also announced that the federal government had agreed to accept 300 D.C. inmates immediately. City officials said that would enable them to reduce the inmate population at the D.C. Jail, which yesterday was about 1,890, to below the court-ordered 1,694 inmate ceiling by early today.

Throughout yesterday, D.C. officials continued shuffling inmates among the city's nine prisons and transferring them to local jails and prisons in Maryland, Virginia and Delaware under special agreements with those states. Several hundred inmates were in dormitories at Occoquan I and II that had not been destroyed by Thursday's fires.

Hudson and diGenova said that the arson at 14 prison buildings and subsequent outbreaks of violence, which left 23 inmates, six corrections officers and three firefighters injured, will be the immediate priority of the investigative body. City officials on Thursday had said 41 people were injured but yesterday revised the number to 32.

One inmate, whom city officials identified as Raymond Thomas, remained in very critical condition last night at D.C. General Hospital. He was struck in the eye by a shotgun pellet, which passed into his brain, during a disturbance Thursday morning involving about 100 inmates.

Prosecutors said the task force will also probe other recent inmate incidents at Lorton, assaults against corrections officers and alleged ongoing criminal activity such as drug and weapons smuggling and drug use at the eight-prison complex in southeastern Fairfax County.

Asked about the prosecutors' criticism, Barry said he would not be drawn into "a big debate about what the U.S. attorney said or didn't say . . . . You the press are trying to get us to pick a fight."

Barry said that the city's Corrections Department has managed to control the prison system's continuing overcrowding problems and, while not naming Hudson or diGenova, said that "most people who criticize the management of our prisons themselves have never managed a prison."

The federal government's decision to accept 300 D.C. inmates was based on what federal officials characterized as Barry's guarantee that the city would quit blaming its prison problems on the Justice Department and move immediately to add prison capacity to care for all the District's criminals.

In a letter yesterday to Attorney General Edwin Meese III, Barry said that the "District of Columbia agrees to insure that space is available in the future to house all D.C. code violators who are transported to the D.C. Jail from the Superior Court." All city inmates must pass through the jail after sentencing before they are assigned to an appropriate Lorton facility.

Federal sources said they believed that Barry was willing to agree to what they called a major concession because he knew that without the federal government's help, the city would not be able to reduce the inmate population at the D.C. Jail in time to avert its shutdown by U.S. District Judge William B. Bryant.

If the population at the jail exceeds the 1,694 cap and is not brought under the ceiling within 48 hours, the jail is to be automatically closed to all new inmates, under an agreement reached last August between the city and attorneys for inmates at the jail in a 15-year-old lawsuit over jail conditions.

"Barry knew that he couldn't possibly get 300 more beds ready by that deadline," according to a source familiar with the negotiations. "He was willing to agree to almost anything we asked for."

City Administrator Thomas M. Downs characterized the exchange of letters differently, saying the new agreement "is a reaffirmation of the need to avoid violating Judge Bryant's decree. The letter states we will take those prisoners and reduce the jail populations and not use the jail" for overflow of prisoners from other institutions.

An attorney for inmates at the D.C. Jail, Ed Koren of the American Civil Liberties Union's National Prison Project, said, "What I'm surprised at is that the feds did not get more concessions when they had these people right where they wanted them . . . . I don't know what that agreement is worth . . . . These people in the past have been willing to sign their name on the dotted line, suggesting 'we'll take care of this crisis, but we might be able to get out of it later.' "

DiGenova said that based on the letter, "We expect movement in the District of Columbia on . . . the construction of a permanent facility," which he said the city apparently had "put off until after the primary in September."

Barry, who first backed construction of a new prison in the city early last year, announced in March that the city would construct a new 700- to 800-bed prison adjacent to the D.C. Jail, but he has repeatedly called on federal officials to take additional D.C. inmates until the new institution can be built.

Barry denied that there have been unnecessary delays in adding new prison spaces, saying that "you can't just snap your fingers and come up with a new facility . . . . We are vigorously working on the site preparation.

"I am doing this in spite of opposition from a significant number of members of the D.C. council," he said. "I am doing this during an election year when building a treatment facility is not popular."

But federal officials had refused to accept more prisoners in the meantime, pointing out that last year they took more than 2,000 D.C. inmates to help the city meet the inmate population cap at the jail. The government ended that agreement in mid-January, saying that the city had not acted quickly enough to add new prison space.

The latest transfers of D.C. inmates into federal prisons will bring the total number of District inmates being housed by the U.S. Bureau of Prisons to 2,500, compared with about 800 prisoners from the 50 state prison systems.

"The spigot has been turned off," diGenova said yesterday.

Under a 40-year-old D.C. law, passed long before Home Rule, all D.C. prisoners are remanded to the custody of the attorney general. As various federal judges have imposed inmate population ceilings on five of the city's nine prisons, Barry and other officials have embraced that law, claiming that the federal government shares responsibility with the city for D.C. prisoners.

Federal officials have argued that the law was enacted to allow escapees from D.C. prisons to be held in jails and prisons in other states, rather than returned to the District. They have pointed out that the city has had responsibility for its own corrections system since long before the law was passed.

Earlier this year, a federal judge refused to require the federal government to bear responsibility for housing D.C. prisoners, saying in open court that for years the city has dragged its feet on reducing prison overcrowding.

Acting Deputy Attorney General Arnold I. Burns said in a letter to Barry that, in the future, buses carrying D.C. prisoners back to the jail from Superior Court are expected to have "immediate" access to the jail.

In recent months, some buses loaded with prisoners have been made to sit for several hours outside the jail while officials there cleared out enough inmates to make room for them.

DiGenova said that the agreement means that the "marshals' buses will not be denied entry, creating futher risks to public safety in the District of Columbia."

The exchange of letters between Barry and Burns was worked out during daylong negotiations Thursday that followed a bungled, middle-of-the-night attempt to persuade Norman Carlson, head of the federal Bureau of Prisons, to take D.C. inmates, sources said.

They said city officials called Carlson early Thursday, in the midst of the Lorton disturbance, but failed to notify the federal officials named by Meese as the Justice Department's prime negotiators on the city's prison problem.

Carlson flatly refused the city's request. But Burns and other Justice Department officials overrode Carlson's decision during a meeting Thursday afternoon, agreeing to take inmates if the city would make the concessions.

Among the D.C. inmates who are being transferred to federal prisons, Barry said, will be the suspected ringleaders of Thursday's daylong disturbance. They earlier had been transferred to the jail, where some were interviewed Thursday night by FBI agents.

In the past, inmates considered to be troublemakers at D.C. prisons have been transferred to federal institutions, far from relatives.

But, Hudson said, inmates identified as participating in the uprising will be returned to federal court in Alexandria for prosecution.

"It should be noted for those prisoners involved in the Occoquan uprising and others at other D.C. institutions," diGenova said at the news conference, "that the net result and reward for their activity for burning down the facilities will be that some of them will be sent as far away as 3,000 miles from their relatives and friends, a fate which they have visited upon themselves."

Staff writer Arthur S. Brisbane contributed to this report.