ATHENS, Greece (AP) — Human rights and aid groups are urging Greece's government to end a "containment policy" of migrants reaching islands in the Aegean Sea from Turkey, warning of worsening conditions ahead of winter.

In an open letter to Prime Minister Alexis Tsipras on Monday, the 19 international and Greek organizations said thousands or refugees and migrants face "abysmal conditions" on Greek islands but are not allowed to travel on to the mainland.

About a quarter of some 60,000 migrants and refugees stranded in Greece are under restriction on the islands as part of an agreement reached last year between the European Union and Turkey.

NATO remains deployed in the Aegean to back up Greek and EU anti-smuggling operations, but the number of daily migrant arrivals has risen in recent weeks.

Albania's Defense Ministry said Monday that its navy patrol vessel Oriku took part in the rescue of 115 migrants believed to be Syrians stranded on a vessel trying to reach Greece. The vessel is part of a NATO deployment in the Mediterranean. No one was reported missing, and the rescued migrants were taken to the Greek island of Chios, the ministry said.