MONTGOMERY, Ala. — The Justice Department has determined that Alabama's prisons are violating the Constitution by failing to protect inmates from violence and sexual abuse and by housing them in unsafe and overcrowded facilities, according to a scathing report Wednesday that described the problems as "severe" and "systemic."

The federal government also is putting the state on notice that it may sue if officials there don't make improvements soon.

"Our investigation found reasonable cause to believe that Alabama fails to provide constitutionally adequate conditions and that prisoners experience serious harm, including deadly harm, as a result," said Assistant Attorney General Eric Dreiband, who leads the department's civil rights division. "The Justice Department hopes to work with Alabama to resolve the Department's concerns."

The report detailed a litany of problems in the state's 13 prisons for men, which together house roughly 16,000 inmates. Those include an overcrowding rate that the Justice Department says ranks among the highest in the nation and a "crisis level" staffing shortage.

In a single week in September 2017, the report found, two inmates stood guard at the doors of a dormitory in one facility while two others repeatedly stabbed a prisoner who eventually bled to death; an inmate at another facility was stabbed and had to be evacuated by helicopters; and a prisoner in a dorm reserved for inmates with good behavior was woken from sleep when two inmates attacked him with a sock filled with metal locks.

The report is only the latest blow to the troubled Alabama prison system, which has come under criticism for violence, overcrowding and a high suicide rate. A federal judge in 2017 ruled that the state has provided "horrendously inadequate" care to mentally ill inmates.

The findings are the result of an investigation opened in 2016 at the end of the Obama administration, which was aggressive in launching wide-ranging investigations into troubled police departments and corrections systems. In a number of cases, those probes led to agreements to make changes under federal oversight. The Trump administration, in contrast, has taken a more hands-off approach.

Before he left office last year, former Attorney General Jeff Sessions, a longtime Alabama senator, released a memo limiting the use of consent decrees struck between the federal government and local agencies under investigation.

Alabama has been trying to address crowding through sentencing reform, but the threat of a federal lawsuit will force the state to address other issues such as sexual assaults in prisons, said Republican state Sen. Cam Ward, who chairs a legislative prison oversight committee.

"We don't have much of a choice. Something has got to happen," Ward said.