Death by violence or disease: prisoners in brutal Assad jails at risk of coronavirus
Amnesty International and Human Rights Watch have long documented abuses in the prisons of President Bashar al-Assad's regime, including executions, torture and starvation.
"If the novel coronavirus spreads in security branches or prisons... this will lead to a major humanitarian catastrophe," said Diana Semaan, Syria researcher at Amnesty International.
"Over the past nine years, we have found that security forces and the heads of the security branches do not provide any kind of medical care for even illnesses considered simple to treat compared to the coronavirus."
The tens of thousands of prisoners are routinely packed into small overcrowded cells in conditions especially ripe for the spread of disease and denied adequate food, medical care and ventilation, rights groups say.
While no outbreak in a Syrian prison has so far been reported, fears were compounded on Sunday after the regime in Damascus announced the country's first coronavirus case.
Read more: Syria Weekly: Activists claim the regime is embarking on a major coronavirus cover-up
"One case of coronavirus in detention facilities can and will be catastrophic," HRW's Sara Kayyali told AFP.
"That's not just because the virus is highly infectious and fatal in some cases, but also because the Syrian government has tortured, mistreated and abused detainees," leaving them highly vulnerable, she said.
'Exponential' rise in deaths
Rights groups have for years documented how prisoners have died not just from executions but also from illness and poor living conditions.
"If coronavirus hits the prisons we are likely to see an exponential increase" in such deaths, Kayyali said.
Syrian activist groups on Monday pressed the government for action, calling for the release of political prisoners and halting of all new arrests.
In a statement signed by 43 non-government groups, many of which are based outside of Syria, they also called on the government to open detention facilities to the World Health Organisation and the International Committee of the Red Cross.
UN envoy to Syria Geir Pedersen on Tuesday made a similar call, urging a "large scale releases of detainees and abductees".
He also appealed for "immediate access for relevant humanitarian organisations to all detention facilities, and urgent steps to ensure adequate medical care and protective measures in all places of detention".
While this has yet to happen, Assad issued a decree on Sunday reducing prison sentences for several crimes.
The decree, shared on state media, did not specify how many people would benefit or if measures were related to the coronavirus outbreak.
But it said prisoners with incurable or terminal illnesses, as well as those over 70 years of age, were free to go.