Tibor Mako, head of the Slovak border and foreign police, offered his resignation to the interior minister over the affair, he told journalists on Wednesday. (Kamil Pisko/(Associated Press)

A failed airport security test ended up with a Slovak man unknowingly carrying hidden explosives in his luggage on a flight to Dublin, Slovakian officials admitted Wednesday.

While the Slovaks blamed the incident on "a silly and unprofessional mistake," Irish officials and security experts said it was foolish for them to hide actual bomb parts in the luggage of innocent passengers under any circumstances.

The Irish were also angry that it took Slovakian authorities three days to tell them about the Saturday mistake and that the pilot of the airplane decided to fly to Dublin anyway even after being told that an explosive was in his aircraft's checked luggage.

The unwitting passenger was identified by Irish police as Stefan Gonda, a 49-year-old Slovak electrician who lives in Ireland.

He was detained for several hours before police let him go without charge Tuesday.

After being informed by the Slovaks, Irish authorities shut down a major Dublin intersection Tuesday and evacuated people from several apartment buildings as Irish army experts examined the explosive.

Security experts said the Dublin episode illustrated the inadequacy of the screening of checked-in luggage — the very point Slovak authorities had sought to test when they placed bomb components in passengers' bags.

Slovak officials said they attached two caches of explosives onto the outside of one man's bag.

The sniffer dog found one explosive, but the police officer in charge failed to remove the second, which was not detected by the dog, from the bag because he was busy, the Slovakian Interior Ministry statement said.

That allowed 85 grams of RDX plastic explosive to travel undetected through security at Poprad-Tatry Airport onto a Danube Wings aircraft.

'Profound regret' for lapse

Slovak Interior Minister Robert Kalinak expressed "profound regret" to the Irish government for the oversight and the delay in alerting authorities.

But his ministry, in a statement, still claimed that "no one was in danger [during the flight] because the substance, without any other components [detonators] and under the conditions it was stored, is not dangerous."

The ministry said it ordered an immediate halt to such tests and took steps to prevent a repeat, while Tibor Mako, the head of Slovakia's border and foreign police whose people carried out the exercise, offered his resignation.

There was no immediate word on whether it would be accepted.

"The aim of the training was to keep sniffer dogs in shape and on alert in a real environment," the ministry said.

Still, details emerging from the failed exercise heightened concerns that basic precautions were not taken, with the ministry saying that when Slovak authorities realized their error and told the pilot of the Danube Wings flight, he still decided to take off with the explosives on board.

It was not clear what any other airport or airline officials, either in Slovakia or Dublin, knew about the failed security test.

The Slovak incident is reminiscent of a French security exercise gone awry six years ago, when a bag of plastic explosives hidden intentionally in an unwitting passenger's luggage went missing.

It wasn't seen again.