IDOMENI, Greece (AP) — The Latest on the flow of migrants into Europe (all times local):

2:50 p.m.

The relief agency Doctors Without Borders, or MSF, says it is no longer staffing the main refugee camp on the Greek island of Lesbos, after police began arresting refugees and detaining them there under a new international agreement.

The action announced Wednesday for the camp at Moria on the island follows a similar move by the United Nations refugee agency.

"We took the extremely difficult decision to end our activities in Moria because continuing to work there would make us complicit in a system we consider to be both unfair and inhumane," said MSF's head of mission in Greece, Marie Elisabeth Ingres.

More than 2,000 migrants and refugees have been arrested since Sunday and are being detained at European Union-supervised registration centers on Greek islands near the Turkish coast.

The agreement reached last week between the EU and Turkey is aimed at cracking down on migration, after more than a million people fled to the EU last year.

2:30 p.m.

Human rights groups and refugee advocates say Hungary is unnecessarily holding hundreds of asylum-seekers in detention and hindering the treatment and recovery of traumatized survivors of torture.

Gabor Gyulai, head of the Hungarian Helsinki Committee's refugee program, said Wednesday that Hungary's practice of detaining asylum-seekers is "not an exceptional measure, it is a widespread practice" which last year led, for example, to having more asylum-seekers in prison-like conditions than in open reception centers.

A report presented jointly by the Helsinki Committee and the Cordelia Foundation, which offers psychiatric counseling to asylum-seekers, found that legal safeguards for torture victims seeking asylum are ineffective, that the detention of torture victims or those suffering from post-traumatic stress disorder fuels re-traumatization and that there are no trained mental health workers in the detention centers.

11:50 a.m.

Refugees and migrants in Greece have staged protests at the country's border with Macedonia and on islands near the Turkish coast, as officials still are unsure when an international agreement to reduce migration would take full effect.

Several hundred protesters camped out at the border disrupted food distribution by charities on Wednesday, and demanded the border be reopened.

Small protests have also occurred at three detention camps on three Greek islands, where arrested migrants and refugees are waiting to be deported back to Turkey.

All refugees and migrants arriving in Greece are being arrested since Sunday, when the agreement between Turkey and the European Union took effect.

Greek officials could not say when the deportations would start, with outstanding legal and practical issues still to be resolved.