A 250-kilogram unexploded aerial bomb from the Second World War has been discovered in Maribor, Slovenia's second largest city, less than two weeks after three similar bombs were safely deactivated in Nova Gorica in the west of the country.

The latest bomb was found on 28 March by construction workers in the industrial part of the Tezno borough. The find has been secured by members of the unit for protection against unexploded ordnance (UXO), who will try to defuse it on 7 April.

Around 50 people who live in the 400-metre radius around the bomb will have to leave their homes during the operation, the local civil protection commander Samo Robič announced on 29 March.

Movement will also be restricted within a broader perimeter of 600 metres, and around 70 businesses in the area will have to adapt their work.

The bomb has mechanical fuses, which will make the operation much safer than if had chemical fuses, said Darko Zonjič, the head of the UXO protection unit.

They will first try to remove the two fuses mechanically, and if they fail, an eight-metre deep hole will be excavated and the bomb will be detonated in it. Zonjič does not think this will be necessary.

Aljaž Leban, a member of the unit, said the device is an American-made AN-M64A1 bomb, which contains around 123 kilos of explosive. If it is detonated, only a small explosion will be triggered, with no major damage in the area expected.

Like Nova Gorica, Maribor is no stranger to WWII-era bombs. Most recently, technicians successfully deactivated a 250kg bomb that was found in the Tezno area during construction work in January 2022. In October 2019 two bombs, one of them weighing 500kg, were defused in the city.

More bombs are likely to be unearthed in Maribor as it was one of the most heavily bombed cities in Yugoslavia in WWII. Between January 1944 and April 1945, 29 Allied bomb raids were carried out, with almost 16,000 bombs dropped on the area, held by the Nazi Germany at the time.