Twelve undocumented migrants drowned when a small boat that was en route to Italy with 27 persons on board sank off the western Greece island of Lefkada at the Ionian Sea on Friday. The victims, including four children aged between 3 to 6 years old, as well as the 15 survivors who were rescued by Greek authorities, are believed to be originating from Syria. The causes of the tragedy are still under investigation. However, experts are suspecting that overload might have led the six-meter long stolen ship to capsize. Following the latest sea tragedy with undocumented immigrants seeking desperately a better future in Europe, Greece called European Union counterparts for immediate coordinated action against human trafficking. "The new tragedy confirms the necessity for the immediate implementation of the initiatives undertaken by the European Union to counter illegal migration," Greek government spokesman Simos Kedikoglou said in a statement released to media. He added that the focus should be on dismantling human trafficking rings, stressing that "the problem is not only Greek, therefore the response should be European." Greece has been a gateway to European Union for illegal migrants originating from Asia and Africa for years. Hundreds drown annually while trying to enter Greece and continue their trip to other European countries.