Greek judicial authorities are investigating the deadly sinking of a migrant boat that was being towed by a coast guard vessel.

The small fishing boat crammed with 28 people had entered Greece illegally. The Coast Guard said it was towing the boat to the small Aegean Sea island of Farmakonissi when it capsized Monday, leaving two people dead and another 10 missing and feared drowned.

Survivors claimed Thursday the boat was being led to Turkish waters to be abandoned. They say they were mistreated by Coast Guard crew, who allegedly stood by as passengers struggled in rough seas.

Merchant Marine Minister Miltiadis Varvitsiotis flatly denies the allegations.

International rights groups have urged a full investigation.