A plan to round up and detain irregular migrants and asylum-seekers in Greece, including those suspected of carrying infectious diseases such as HIV, has been called "deeply alarming" by Amnesty International.
Those considered vulnerable to such diseases, based on their country of origin, poor living conditions, occupation as sex workers or their drug use, will be targeted.
"These deeply alarming measures specifically target the most vulnerable people based on discriminatory criteria," said Jezerca Tigani of Amnesty International.
"The Greek authorities must withdraw such measures immediately, which will only exacerbate the stigmatization of migrants and asylum-seekers in the country."
The Greek authorities recently announced plans to establish a series of immigration detention centres where irregular migrants arrested in sweep operations in Athens will be held for deportation.
"Immigration-related detention is used only a last resort, and arresting irregular migrants without seeking any alternative measures violates Greece’s international obligations," said Jezerca Tigani.
"It is especially concerning that those eligible for international protection also face being detained. Migrants and asylum-seekers are not criminals and should not be treated as such."
There are no appropriate facilities at Greece's borders for the identification of those in need of international protection, such as victims of torture and unaccompanied or separated asylum-seeking children.
The authorities have pledged to arrest those not carrying immigration papers, but Amnesty International has learned of severe difficulties for those attempting to apply for asylum.
Many asylum-seekers living in the capital Athens are afraid to leave their homes for fear of arrest or violence.
One asylum-seeker told Amnesty International: “I come every Saturday (to submit an asylum application) but nothing happens. Last week, they took no applications. I have no papers. (The police) see me on the road with a dark colour and ask if I have papers. I do not have any and then they arrest me. It is a big problem. Those who do not have papers are detained. I stay at home and sleep…"
Amnesty International understands that migrants and asylum-seekers diagnosed with an infectious disease will be transferred to special hospital units for treatment under police guard.
Another measure requires migrants to have a health certificate in order to be allowed to work.
Many migrants and asylum-seekers live in Greece live in squalid conditions due to the country's ineffective asylum system, while detention conditions in many immigration centres amount to inhuman and degrading treatment.