Security was being tested at Bratislava Airport
Irish police have released a man held over an explosives find, after Slovak authorities admitted planting them in his luggage as part of a security test.
The explosives were among eight contraband items placed with passengers at Bratislava Airport last weekend, broadcaster RTE reported.
The 49-year-old man unwittingly brought the material into Dublin when he returned from his Christmas holidays.
He was arrested on Tuesday morning but has since been released without charge.
Minister for Justice Dermot Ahern said he was very concerned that Irish police had not been alerted for three days.
Airport security detected seven of the illicit items, but the eighth - 90g of research development explosive - managed to escape detection.
Slovak authorities were reportedly trying to test screening procedures for checked-in luggage by placing items with unwitting passengers.
Slovak police alerted their Irish counterparts on Tuesday morning, and the man's flat near the city centre was cordoned off while bomb disposal experts removed the explosives for further examination.
The Irish Army said passengers had not been put in danger because the explosives were stable and not connected to any essential bomb parts.
The Slovak minister for the interior has expressed his government's "profound regret" to Mr Ahern.
An Irish government spokesman said Mr Ahern had "ordered a full report into what has transpired".
Airport security has been stepped up in many countries following an alleged plot to bomb an airliner over the US city of Detroit on 25 December, though it was not clear if the Slovak test was linked to such efforts.
A failed test of security at Slovakia's Poprad airport resulted in a 49 year-old man unknowingly carrying plastic explosives from Slovakia to Dublin, Ireland. The explosives were concealed so well that the man did not find them when he unpacked his bag at his apartment.

On Saturday, Slovak authorities planted contraband in passengers' luggage at Poprad's Poprad-Tatry Airport without the knowledge of passengers.  Seven of the eight items were recovered, while an eighth made its way to an apartment in Dublin.  Slovak authorities realised on Tuesday that one package of explosives were missing and notified Irish authorities who searched the man's apartment.

During the search, parts of Dublin's inner-suburbs were sealed off and evacuated causing disruption to residents and businesses.  At the apartment authorities found the package and arrested the man under anti-terrorism laws; he was later released without charge after it was established he was innocent.

The man, a Slovakian electrician had been living in Ireland for some time. He was holidaying in Slovakia over Christmas.

Ireland's Department of Justice, Equality and Law Reform issued a statement saying, "Following contact earlier today from the Slovakian authorities with the Airport Police at Dublin Airport, members of the Garda Síochána have recovered a small quantity of explosive material from the luggage of a passenger who had flown into Dublin from that country on Saturday last."

The package contained 90 grams (3 ounces) of the plastic explosive RDX, also known as cyclonite or hexogen. According to Commandant Gavin Young, a spokesperson for the Irish Defense Forces, "On their own, this type of explosive does need to be combined with other elements to make it into a bomb, but obviously this type of high-grade explosive is potentially extremely dangerous."

Slovakia's Minister for the Interior Robert Kalinak has apologized to Irish Justice Minister Dermot Ahern over the incident and expressed his “profound regret”. Irish authorities are now investigating the incident and the government has ordered for a full report to be delivered.

The Irish Opposition has expressed concern about the incident. Labour Party spokesman Joe Costello said "This incident led to the closure of roads in the area, the evacuation of businesses and the lives and safety of residents could have been put at risk. We also need to know what protest the government is going to make about this breach of our security."