At least 16 people, including six children, drowned Saturday after a migrant boat capsized in the Aegean Sea, the deadliest disaster in the area since a controversial deal two years ago between the EU and Turkey to try to stem the flow of migrants to Europe
Another three people are missing after the boat went down overnight off the island of Agathonissi as it was carrying migrants from Turkey to Greece, police said.
Two women and a man who managed to swim to safety on the island sounded the alarm and several vessels and a helicopter joined in the search for bodies and the missing.
"We cannot and must not tolerate people, children, losing their lives in the Aegean," Greece's Migration Minister Dimitris Vitsas said.
The solution, he said, is to ensure "safe routes and procedures for refugees and migrants, and to fight against trafficking".
Another two migrants died on Saturday near the land border with Turkey when the truck they were travelling in overturned trying to avoid a police check, the authorities said.
The UN refugee agency the UNHCR said that 500 people had perished or gone missing in the Aegean in the past two years -- adding to the 1,000 who drowned in the narrow channel between Greece and Turkey in 2015 and 2016 at the peak of the migration crisis.
Saturday's Aegean tragedy came almost two years to the day since the EU and Turkey struck a multi-billion euro deal to curb the number of migrants and refugees trying to make their way to Europe.
"These deaths are the result of the 'fortress Europe' policy," activist Thanassis Kourkoulas said during a demonstration in Athens against the deal.
"Open the borders," chanted hundreds of protesters, including many refugees.
European border agency Frontex said last month that in 2017, the European Union saw the lowest number of detected illegal border crossings since the migrant crisis began four years ago.
The number dwindled to 204,700 from 1.8 million in 2015, it said. The drop was especially observed on the eastern Mediterranean migratory route between Turkey and Greece, and the central route between Libya to Italy.
But hundreds of people, mostly Syrians, Afghans and Iraqis, continue to land every month on the Greek islands that lie just a stone's throw away from the Turkish coast.
The UNHCR, said 4,000 refugees have arrived since early 2018 alone.
Greece is detaining thousands of migrants in overcrowded squalid camps. many of whom are trying to apply for asylum.
The EU-Turkey deal has been criticised by humanitarian groups deterring people from coming who under international law must be granted asylum, such as those fleeing war-torn countries like Syria.
Under the agreement, all new irregular migrants crossing from Turkey into Greek islands must be returned to Turkey. These include both refugees fleeing conflict and persecution as well as economic migrants.
In addition to providing billions in funds in return, the EU agreed other concessions to Turkey such as to accelerate plans to bring in visa-free travel for its nationals and boost negotiations for its membership of the bloc.
But these have stalled due to Brussels charges that Ankara has committed massive human rights violations in the wake of a failed coup in July 2016.