MILAN - Police in Italy, Hungary and Slovenia on Saturday arrested four people in a coordinated operation targeting a group suspected of smuggling illegal migrants into Italy from the Balkans, Italian police said.Two of the suspects were arrested in northern Italy, one in Budapest and one in the Slovenian city of Maribor, they said. The four are all charged with criminal conspiracy and aiding and abetting clandestine migration.The suspects are part of a trans-national criminal group of Pakistani origin that is based in Milan, the Italian Carabinieri police said in a statement.The organisation transported Pakistani, Bengali and Afghan migrants from Hungary into Italy and northern European countries, packing them into delivery vans and using fake documents, the statement said.The police said the business generated returns close to 500,000 euros a year.More than one million migrants, many fleeing conflicts in Syria, Iraq and Afghanistan, have poured into Europe through Greece since last year, with the Balkans being the preferred route to Western Europe.The number of migrants has fallen sharply in recent months, however, due to much tighter policing, the erection of walls on some stretches of border and a deal between the European Union and Turkey which involves returning illegal migrants arriving in Greece back to Turkey.