Greece is a main entry and transit point for African, Asian and Middle Eastern migrants desperate to get to Europe in search of protection and a better life. The Greek government is under pressure from the European Union to stem the influx.
Two years ago, the authorities began an operation detaining migrants and asylum-seekers, some of whom say they are targeted indiscriminately despite having papers to work and live in the country.
In a small shop in the Kypseli neighborhood, a group of African migrants has met for a chat. They converse in a low tone, worried of their surroundings.
The shop owner, Chuks Ibe, says he has been in Greece for 20 years without papers and most of his customers are Africans.
"They [Greeks] don't accept you as a black man. Even in my shop you can see a Greek person once in awhile," said Ibe. "I am being patronized by foreigners, my African brothers, but Greeks before they come [it] is late in the night, they are desperate in need of something they will come to you, some they see a black man they leave."
The father of five also says the Greek government does not recognize his children as Greek citizens.
"The children who are born here they don't care about them, they don't give them money, they don't give them citizenship is a problem," he said. "I have five children here but they see them as a foreigners."
Daniel Ikechukwu has lived in Greece for 13 years. Every six months he has to pay 600 euros to renew his residential and work permit. But he says he cannot work now, because the last time he went to renew his permit he was told to come back after six months.
"The woman I met there, I told her, 'See how many years I have stayed in Greece with this paper," he said. "I paid everything, I paid my tax [when] I was working in the airport and am a good worker. You people stopped me working, my company pays you 350, 250 depending on what I make in a month.'"
Another migrant, Emeka, says he has documents that allow him to stay in the country but frequently he is stopped by police.
"Imagine a policeman in this country can ask you to lie down on the floor on the road and you have a paper, even if you show him the paper he will still tell you to go down on the floor just for nothing," said Emeka.
In a report last year, Human Rights Watch said Greek police have detained tens of thousands of people presumed to be irregular migrants. It said people who appear to be foreigners are subjected to routine stops, unjustified searches of their belongings, insults and in some cases are physically abused.
The rights group also said even those with legal documents are stopped and officers transfer them to a police station, where they can be held for hours pending verification of their status.
It noted Greek authorities have a right to control irregular immigration and a duty to improve security on the streets for everyone, but they have also to regulate police powers.