Turkey, which is currently sheltering the world’s largest refugee population, has been unlawfully detaining and deporting refugees and asylum-seekers back to war zones in a clear breach of international law, Amnesty International said in a report released Wednesday. The human rights group also said that the European Union risked being complicit in the illegal deportations as it had recently pledged 3 billion euros ($3.26 billion) to Turkey in exchange for help in curbing the influx of refugees into the continent.

“We have documented the arbitrary detention of some of the most vulnerable people on Turkish soil,” John Dalhuisen, Amnesty International’s director for Europe and Central Asia, said in a statement accompanying the report. “By engaging Turkey as a gatekeeper for Europe in the refugee crisis, the EU is in danger of ignoring and now encouraging serious human rights violations. EU-Turkey migration-related cooperation should cease until such violations are investigated and ended.”

As part of an EU-Turkey pact finalized late last month, Turkey -- a major transit point for people fleeing Syria, Iraq and Afghanistan -- agreed to strengthen its western borders to stop the flow of migrants and refugees toward the EU. In return, European leaders agreed to “re-energize” long-stalled talks over Turkey's bid to join the 28-nation bloc.

“While the EU is increasingly anxious to ensure Turkish cooperation in reducing irregular migration, it is allowing its funds to be used for equipment and infrastructure in facilities from which refugees and asylum-seekers are being unlawfully pressured to return to countries like Syria and Iraq,” Amnesty said, in its report.

Refugees and asylum-seekers were purportedly detained without explanation or legal grounds in camps in Turkey’s border provinces. Many of these detainees also alleged that they had been physically abused by Turkish authorities.

For instance, a 40-year-old Syrian man, whose name was not disclosed, told Amnesty’s investigators that at some point between late September and late November, he had been confined to a room in an EU-funded removal center in Turkey’s Erzurum province for seven days with his hands and feet shackled.

“The EU is currently seeking to expand its funding of Turkey’s centers for refugees and migrants. … It is imperative that it establish effective independent monitoring mechanisms of conditions and practices in such centers, to ensure their human rights compliance,” Amnesty said, in the report. “Continued funding must be conditional on such compliance.”

However, the Turkish government, which has, in the past, accused European nations of shirking their responsibilities in tackling the region’s worst refugee crisis since World War II, categorically denied the allegations, reportedly saying that all returnees were being independently interviewed by the United Nations refugee agency.