A 250-kilogram aerial bomb from the Second World War has been discovered in Nova Gorica, a city on the border with Italy. Slovenian technicians are expected to attempt to defuse it on Sunday but since nearby residents will have to be evacuated on both sides of the border they are coordinating their plans with Italy.

The bomb contains around 100 kg of explosive and is currently secure, Darko Zonjič, head of the national unit for the protection against unexploded ordnance (UXO), told reporters on 18 July.

The bomb has two mechanical fuses, which Zonjič said was "very fortunate". "If we were dealing with chemical fuses, the measures would be completely different," he said.

The plan is to deactivate the bomb on Sunday but the date has to be confirmed by the local authorities in Gorizia, the city on the Italian side of the border, where a potential explosion would also be felt.

By surrounding the site with hay bales, the zone of impact of a potential explosion will be reduced from a 1,200 metre to 400 metre radius.

All residents in a 400 metre radius will be evacuated and movement will be restricted in a 600 metre radius. The detonation process is planned to take three to four hours.

Two bomb technicians will attempt to remove the fuses. If they fail to do so in an hour, they will proceed with a controlled detonation, lowering the bomb into a hole and cutting into it from a distance. The bomb could burn "if we are lucky", said Zonjič. Otherwise it will explode. "We plan that we will succeed with removing the fuses," he said.

The bomb was discovered on 17 July during construction works near the Nova Gorica train station. It was hit by an excavator and slightly damaged, "so it is lucky that a catastrophe didn't happen then," said Nova Gorica Mayor Samo Turel.

The bomb is thought to be an English aerial bomb from WWII. A similar explosive was found in Maribor in 2022 and was successfully deactivated.

Unexploded ordnance finds are not a rarity in Slovenia. In the western region of Primorska most stem from the First World War, the area being the site of battles between the Austro-Hungarian and Italian armies along the Isonzo Front.

Several aerial bombs have been found in Maribor, a city occupied by the Nazis in the Second World War that was bombed by the allies in 1944 and 1945. In 1998 three 500 kg bombs were discovered during the construction of a Maribor shopping centre.