ATHENS — Greek islanders protested Tuesday in Athens outside Greece’s ministry for migration over the increasingly precarious, overcrowded conditions faced by newly arriving migrants and refugees.

The mayors of the islands of Lesbos, Chios, and Samos, along with dozens of residents, traveled to the mainland to demand the government take measures to reduce overcrowding.

‘‘There are large numbers of people who are living in inhumane conditions, in appalling conditions, dangerous conditions, and at the same time the social cohesion on our islands is in danger,’’ Lesbos Mayor Spyros Galinos said, explaining why he wants the number of migrants on his island reduced.

Under a European Union-Turkey deal reached last year to reduce the number of migrants coming in, those arriving on Greek islands from the Turkish coast are held in camps on the islands and face deportation back to Turkey unless they successfully apply for asylum in Greece.

The lengthy process has led to severe overcrowding. On Lesbos, about 6,500 people are stuck in facilities designed for just over 2,300.

‘‘There is no room, there is no solution with this policy,’’ said Galinos. ‘‘If we don’t react now . . . the problem will continue to grow. At some point, the bubble will burst and things will be completely unmanageable.’’

Human rights groups have also repeatedly voiced concerns over the conditions on the islands, especially in winter.

Authorities have been moving hundreds of migrants deemed to be vulnerable from the island to camps on the mainland. But with more people arriving, the move has not relieved pressure on the overcrowded facilities on the islands.

Associated Press