European Union officials have expressed concern about a possible increase in human trafficking next year during the European football championships in Poland and Ukraine, and the Summer Olympic Games in London.

EU anti-trafficking coordinator Myria Vassiliadou said Tuesday that sporting events are a “hub for criminal gangs.” She noted that similar large sporting events in the past had been accompanied by a spike in prostitution and trafficking.

Vassiliadou spoke to reporters at an EU conference in Warsaw, Poland, which currently holds the EU's six-month rotating presidency.

She added that the European Union is trying to raise awareness about the problem. But Vassiliadou said the 27-member bloc has little power to crack down on human trafficking, and the responsibility largely rests with EU nations.