At least 28 migrants have drowned after attempting the crossing from Turkey to Greece.
14 youngsters were among those who died when a wooden boat, with more than 125 people on board, capsized.
The Greek coastguard says nearly 100 others were either rescued, or managed to swim to safety to a remote island north of Kos.
Germany's introducing temporary checks on its border with Austria, to limit the influx of refugees.
Around 16 thousand people have arrived in Germany this weekend.
Officials are warning resources are under huge strain.
