The European Union demanded Friday that Slovak authorities explain how an airport security drill mistakenly allowed a block of explosives onboard a flight to Ireland on Jan. 2.

Spokesman Fabio Pirotta said the EU wants formal notification about the drill, in which Slovak authorities put 96 grams of explosives into the check-in baggage of an innocent Slovak man travelling from Poprad-Tatry Airport to Dublin.

Pirotta said the EU found out about the error through media reports.

The drill was meant to test the skills of Slovak bomb-sniffing dogs. While the explosives were detected, police officers failed to remove them from the man's luggage.

The angry Irish government wants to know why it took Slovakia three days to tell it about the mistake, and why the pilot of the plane decided to fly even though he knew the explosives were in his aircraft's cargo hold.

After being told of the mistake, Irish security personnel had to evacuate several apartment buildings in Dublin while they examined the explosives.

The traveller, Stefan Gonda, a 49-year-old Slovak electrician who resides in Ireland, was detained by Irish authorities for several hours before being released Tuesday without charges.

On Thursday, Slovak Interior Minister Robert Kalinak accepted the resignation of senior police official Tibor Mako over the botched drill.