LESBOS, Greece (Reuters) – More aid agencies working to alleviate conditions of refugees and migrants arriving in Greece said they were joining a boycott of detention centers on Wednesday, angered at an EU deal they say runs roughshod over human rights.

Human rights organizations are incensed at a pact between the EU and Turkey under which hundreds of new arrivals have been detained since Sunday, for fast-tracking registration and asylum applications. Those refugees or migrants who fail will be sent back to Turkey.

Aid agencies said cooperating with the Greeks at detention centers would make them complicit to a practice which was ‘unfair and inhumane’.

U.N. refugee agency UNHCR and aid organization Medicins Sans Frontieres (MSF), a major contributor to the relief effort, announced they would be cutting back assistance on Tuesday. Two other aid agencies joined them on Wednesday.

“The IRC alerted the (Greek) coast guard on Monday that we would not transport the world’s most vulnerable people to a place where their freedom of movement is impeded upon,” said Lucy Carrigan, a regional spokeswoman for the International Rescue Committee (IRC).

The IRC will continue to support those at another makeshift camp, she said.

The Norwegian Refugee Council, a major non-governmental organization, said on Wednesday it was suspending most of its activities within a detention center on the Greek island of Chios.

“We are extremely close to be in a position where this site is dangerously overcrowded … We have a large number of refugees including pregnant women and children lying on the concrete floor in the reception hall,” said Dan Tyler, a protection adviser for the council.

Tension within the facility was building up and there had already been demonstrations, he told Reuters.

Greek authorities said they needed help. “We need these international organizations, particularly the UNHCR which is of great assistance to us. Naturally we want it to stay, under certain rules, of course,” Citizen Protection Minister Nikos Toskas told Greek radio.

A government source said migration minister Yannis Mouzalas was trying to coax aid organizations back.

“He is the best placed to mediate with these groups,” the source said. Mouzalas, a medical practitioner, had been extensively involved with aid agencies and participated in relief missions before his cabinet appointment in Greece’s leftist-led government last year.

More than 147,000 people, many fleeing conflict in the Middle East and Asia, have arrived in Greece by sea this year. Almost one million arrived in Europe via Greece in 2015.

(Additional reporting by Stine Jacobsen in Oslo, Renee Maltezou and Angeliki Koutantou in Athens; Editing by Raissa Kasolowsky)