Ninety-two migrants were found almost naked and bruised after allegedly being forced across the Evros river into Greece, Athens said on Sunday.
EU border agency Frontex confirmed the arrival of the group in circumstances which the Greek ministry for civil protection said sent out an “inhuman image”.
“The Frontex officers reported that the migrants were found almost naked and some of them with visible injuries,” said Frontex spokesperson Paulina Bakula.
The UN refugee agency, UNHCR, said in a tweet that it was “deeply distressed by the shocking images of 92 people, who were reported to have been found at the Greek-Turkish land border, stripped of their clothes”.
Bakula, speaking from Frontex’s Warsaw HQ, said Frontex officers worked with Greek authorities to provide the migrants — mainly Afghans and Syrians — with immediate assistance.
She added the organisation had informed the agency’s fundamental rights officer of a potential rights violation.
Greek minister for civil protection Takis Theodorikakos accused Turkey of "instrumentalising illegal immigration" amid a war of words between the two neighbouring countries over migration.
Speaking on Skai television, Theodorikakos said many of the migrants told Frontex that "three Turkish army vehicles had transferred them" to the river which acts as a natural border.
In a series of scathing comments on Twitter, the Turkish presidency denied any responsibility for the migrants and blamed Greece for the "inhuman" situation.
"We urge Greece to abandon its harsh treatment of refugees as soon as possible, to cease its baseless and false charges against Turkey," wrote President Recep Tayyip Erdogan’s top press aide Fahrettin Altun.
"With these futile and ridiculous efforts, Greece has shown once again to the entire world that it does not respect the dignity of refugees by posting these oppressed people’s pictures it has deported after extorting their personal possessions," he added in tweets delivered in Turkish, Greek and English.
Turkey’s Deputy Interior Minister Ismail Catakli called on Greece to stop what in a tweet he termed its "manipulations and dishonesty."
Greek minister for migration and asylum, Notis Mitarachi, had Saturday described the incident as a "shame on civilisation."