In a press release, the Greek organization said it understood and appreciated Greece's right to protect its borders but said that this could not override its obligations under European and international law to respect the rights of refugees seeking political asylum.
The group claimed that the Xenios Zeus operation was apparently being conducted without any precautions to identify refugees meriting protection from other migrants.
It also criticized the country's failure to effectively process asylum claims submitted to authorities by immigrants -- long the focus of complaints by international inspectors. The organization claimed that in some cases Greek police officers make migrants unwittingly sign documents terminating their applications for asylum and thus opening the way for their deportation, often to countries where their lives might be in danger.
Police continued their crackdown on undocumented immigrants in central Athens on Thursday following the detention of another 52 people on Wednesday after raids on unlicensed stores, brothels and street sweeps. The arrests led to another three suspected prostitutes reportedly testing positive for the HIV virus which can lead to AIDS.
Police, who arrested more than 1,400 migrants in a huge raid over the weekend, and are gradually deporting the detainees, said that the sweep, code-named Xenios Zeus, would continue over the coming days.