Around 54,000 people were evacuated from the southern Italian city of Brindisi on Sunday as experts worked to defuse a World War Two bomb, authorities said.

Corriere della Sera daily said the operation was the biggest peacetime evacuation in Italy, with more than 60% of the city’s residents forced to vacate a “red zone” in a radius of 1,617 meters from where the bomb was found.

The British bomb, believed to have been dropped on the city in 1941, is 1 meter long and contains 40 kgs of dynamite, authorities said. It was found by chance last month during refurbishment works at a cinema theater.

The city’s airport, train station, two hospitals and a prison were shut down and evacuated as part of the operation, which authorities expect to be completed around lunchtime.