The 250kg US bomb was discovered by a villager near Vurberk Castle with a metal detector last week while he was playing a treasure hunt game with his kids.

Instead of notifying authorities right away, he transported the device to his home yard, jeopardising the lives of his family and of his neighbours.

Today's operation went as planned, with virtually no impact on the environment, Stanislav Lotrič from the Civil Protection and Disaster Relief Administration told reporters.

The bomb was first removed from the finder's home by means of a special cable system and placed into a hole dug out 30 metres away, where it was dismantled by members of the unexploded ordnance protection unit.

Two minor explosions followed within a space of ten minutes. The second one was a bit louder and there was a smoke seen billowing from behind a hill.

The first explosion occurred when the rear part of the bomb containing the fuse mechanism was remotely removed. This piece then caught fire, which caused the second explosion.

The other part of the bomb remained intact. There is still some explosive left in it, but it poses no risk, UXO defence unit spokesman Igor Boh said, adding that the explosive would be destroyed at the UXO clearance range.

"Our expectations turned out to be right and we have neutralised the device in the best way possible," said Boh.

The operation did not begin until the area in a radius of one kilometre from the bomb had been evacuated. The area comprises 150 houses with more than 450 residents but considering that many are away on holidays, the local authorities estimate only just over a hundred actually had to leave their homes.

In preparation for the operation, the area around Vurberk Castle had been inspected for potential further UXO, but even though none were found it is impossible to rule out that any may still be left, Lotrič said.

He estimated the costs of the operation at between 15,000 and 20,000 euro, which will be covered by the state.

The man who found and moved the bomb is facing public nuisance charges, an offence that carries up to five years in prison.