At least six inmates are reported to have died after riots in Italian jails over hard-line measures introduced to contain coronavirus in the country.
Footage on social media showed a number of prisoners standing on the roof of the San Vittore prison in Milan.
Other images show smoke rising from the jail in Milan after prisoners set fire to the building. Local media said at least two of the deaths in a prison in Modena are being blamed on drug overdoses.
Prisoners at jails in Naples and Poggioreale in the south, Frosinone in central Italy and at Alexandria in the north-west also revolted over measures including a ban on family visits, unions said.
Similar scenes played out in Padova in the north and Bari, Foggia and Palermo in the south, media reports said.
According to the secretary general of the prison officers union in Seppe, Giovanni Battista Durante, about 80 prisoners at the Modena prison were transferred to other jails after they managed to reach an outside yard in a bid to escape.
"We are told other prisoners inside the jail have barricaded themselves in and probably have illegal weapons," he said, and the jail had been "completely destroyed".
The uprisings came as Italy issued new nationwide rules to try to stem the spread of the virus, which has killed 366 people so far and infected 7,375 in the country.
The quarantine has effectively locked down 16 million people in northern Italy.
It is now the second-worst affected country in the world, behind China.
"We had already warned tensions were growing in prisons, and that we feared it could end in tragedy," said rights group Antigone.
"All necessary measures must be taken to ensure prisoners their full rights, stopping this escalation of tension and preventing others from dying. One death is already too much."
At the Torre del Gallo jail in Pavia, south of Milan, two guards were reportedly taken temporarily hostage, enabling prisoners to steal the keys and release their fellow convicts.
Italian media said there were unconfirmed reports of violence against guards and between rival prison gangs.
The Poggioreale prison in Naples suffered millions of euros in damages after about 1,000 prisoners rioted, la Repubblica reported.