Italian penitentiary police said Monday six inmates protesting virus containment measures at a northern Italian lock-up have died after they broke into the infirmary and overdosed on methadone.

The protest Sunday in Modena was among the first of more than two dozen riots at Italy’s overcrowded lock-ups that grew Monday.

Human rights advocates have been warning that increasing tensions over fears of coronavirus were hitting inmates particularly hard, especially after restrictions were imposed on family visits to prevent transmissions.

Smoke and flames were shown on social media from the prison of San Vittore in Milan.

On Monday, inmates climbed onto the roof of the San Vittore prison in Milan and held up a painted sheet reading “Indulto,” Italian for pardon.

According to ADNKronos, prisoners took control of the facility.

Donato Capece, secretary general of the penitentiary police union, accused the government of abandoning the prison system, refusing to provide sufficient measures to prevent the spread of the virus among inmates and leaving guards on their own to deal with prisoners who could now only speak to relatives by phone or Skype.

“The administration is completely absent,” he told The Associated Press. “They have left the penitentiary police in jeopardy.”

He confirmed six inmates at the Modena prison had died from overdoses. He ticked off the more than two dozen prisons where protests were underway, including in Foggia where some prisoners had escaped.

Italy’s overburdened court system has ground to a near halt because of virus containment measures.

A prison police union told IlTempo.it some inmates have attacked the infirmaries. Several fire personnel intervened in the riots inside the Rebibbia prison.

Members of prisoners’ families were seen outside the gates.

This story is being updated with the latest details.