Greek officials confirmed 78 refugees have been rescued from crippled smugglers' boats in two separate incidents in the eastern Aegean Sea.
A patrol vessel from the European Union's Frontex border agency picked up 56 people off the island of Chios, while a Greek coast guard crew rescued another 22 off the nearby islet of Panagia.
More than a million refugees and other migrants have reached the Greek islands from nearby Turkey since the beginning of 2015, on their way to Europe's prosperous heartland.
But arrivals have decreased sharply after March 20, when an agreement between the EU and Turkey on addressing the influx came into effect.
A total of 87 people reached the Greek islands on Wednesday.
Earlier, German Chancellor Angela Merkel warned Europe risks succumbing to nationalism by closing borders as a solution to the migrant crisis.
Austria has said it will close the key Brenner crossing with Italy if necessary to stop the flow of migrants northward after they are rescued from smugglers' boats off Italy's coast.
Italian Premier Matteo Renzi, after holding talks in Rome with Ms Merkel, described Austria's strategy as "mistaken," ''anachronistic" and "unjustified".
Ms Merkel told reporters the crisis must be resolved "in a way different from closing borders".
She added: "We can't close borders... We must be loyal to each other."
Ms Merkel said EU nations must defend the Schengen border-free travel agreement or "else we risk falling back into nationalism".