The Greek coast guard prevented almost 600 irregular migrants from crossing the Aegean Sea from Turkey, a spokesperson said Monday.

Five sailboats and four dinghies had set off from the Turkish coasts early in the morning, the spokesperson said.

Human rights advocates and leading media outlets have frequently reported illegal pushbacks and other rights breaches by Greek authorities violating European Union and international law.

Besides seaborne pushbacks, Greek border forces are also accused of apprehending and forcibly expelling migrants who manage to cross into the country by land.

In February, at least 19 irregular migrants were found frozen to death near the Turkish-Greek border after being pushed back to Turkey by Greece.

Turkish officials criticized Athens for the inhumane and degrading treatment of irregular migrants, saying those who were found dead had been stripped of their clothes and shoes by the Greek border guards. Greece denied any involvement.