Brussels: The European Union's Frontex border agency is threatening Greece with a withdrawal of funding due to 12 cases of migrant rights violations being investigated against the country, Politico reported on Thursday.

According to Namibia Press Agency, the majority of the ongoing investigations concern the alleged forced expulsion by Greek migration services of thousands of people from the country's land and sea borders. This practice is prohibited by the UN Convention on the Status of Refugees and international law, the newspaper reported.

The Greek government, in its turn, issued a denial of the allegations.

On Wednesday, German newspaper Bild reported, citing sources in the German and Greek security agencies, that the Bulgarian and Greek authorities did not prevent a loophole in the Schengen zone rules which allows tens of thousands of migrants to fly to Germany under the pretense of tourism, where they then apply for refugee status again.