A group of 36 refugee nongovernmental organizations (NGOs) issued a call Tuesday to meet with Pope Francis, informing the religious leader of the harsh living conditions migrants face in hot spots like Lesbos ahead of his trip to Athens this weekend.

NGOs in Greece have repeatedly decried slow asylum procedures and the alleged mistreatment of migrants and refugees in camps and at the EU member's borders, which Greece's government denies.

Francis has denounced the "hostility" and "exploitation" migrants in Europe have faced and next month will make an official visit to Athens and the island of Lesbos, one of the main gateways for refugees to Europe.

Lesbos was home to Europe's largest refugee camp until it burned down last year.

The NGOs said they were "hoping for a message of solidarity" from Francis to aid "persecuted human brothers" and urged the Greek government to integrate refugees better "instead of isolating them in prison camps."

The NGOs also voiced concern about the "growing refusal of EU member states to contribute in a concrete and effective way to the protection of human lives."

The Greek government recently opened two new camps on the Aegean islands of Leros and Kos, but human rights activists criticized restrictive measures including barbed wire fencing and surveillance cameras.

Greece was at the center of Europe's 2015 migrant crisis peak as its Aegean islands were the first destination for mainly Middle Eastern migrants entering the European Union from Turkey.

According to U.N. estimates, around 96,000 refugees and asylum seekers live in Greece.