Zimbabwe released at least 320 prisoners from its jails on Saturday to ease congestion in the country’s notoriously overcrowded jails as a second wave of the coronavirus devastates the country.

The move comes amid growing allegations that a government crackdown has sent dozens of activists, journalists and opposition leaders to prisons.

The prisoners were released under an amnesty program established by President Emmerson Mnangagwa in 2018, the year after he seized power, ending decades of the strongman rule of Robert G. Mugabe. The amnesty does not include prisoners convicted of crimes that include murder, human trafficking, sexual offenses and treason.

Most of those released on Saturday had been convicted of nonviolent crimes, according to Zimbabwe’s Prison and Correctional Service, but were being held in the infamous Chikurubi Maximum Security Prison. That is the country’s largest correctional facility, and it is known for overcrowding and unsanitary conditions.

For years, Zimbabwean officials have grappled with severely strained jails that human rights organizations have slammed for unsafe conditions. The country’s prisons have the capacity to house 17,000 prisoners at most, but they held around 22,000 when Mr. Mnangagwa established the amnesty.

Concerns about prison overcrowding grew more urgent when the pandemic struck last year, and the virus threatened to engulf the prison population. From March 2020 to June 2020, the government released 4,208 prisoners under the amnesty order.

The decision to release the latest round of prisoners comes after the variant first identified in South Africa, B.1.351, flooded into Zimbabwe at the start of the year, straining a system that already lacked enough drugs, equipment and medical staff. To date, Zimbabwe has recorded nearly 38,000 coronavirus infections, including 1,551 deaths, according to the Africa Centers for Disease Control and Prevention.

In February, the country started a national vaccine campaign with 200,000 doses donated by the Chinese vaccine maker Sinopharm. The country is set to receive an additional 1.1 million doses as part of Covax, a global sharing program that is distributing vaccines to poor and middle-income countries.