A World War II bomb discovered during construction work in Bratislava prompted large-scale evacuations and the suspension of traffic and public transportation Tuesday morning, officials said.

The unexploded ordnance, weighing about 500 pounds (225 kilograms), was found Monday evening and prompted authorities to clear several blocks in the city center, including a major bridge spanning the Danube River. Officials said bomb disposal experts were scheduled to defuse the device by midday.

Public transportation in affected areas was halted and all vehicle traffic was stopped during the morning rush hour while emergency services established a safety perimeter. City officials advised residents and businesses within the evacuation zone to follow instructions from emergency personnel and warned that disruptions could continue until the scene was declared safe.

The area where the bomb was found includes an oil refinery that was targeted in Allied bombardments in 1944. Slovakia was under a Nazi-aligned government during the Second World War, and unexploded ordnance from that period is occasionally uncovered during construction projects or excavation work across parts of Europe.

Authorities mobilized police, fire and medical teams to support the evacuation and to secure the site while specialized bomb disposal technicians prepared to render the device safe. No injuries were reported in connection with the discovery, and officials did not immediately release details about the bomb’s condition or make and model.

City officials said they would provide updates after the disposal operation. Until then, commuters were advised to seek alternative routes and expect continued delays as crews work to ensure the ordnance is fully neutralized and the area cleared for residents and traffic to return.

The discovery underscores the lingering hazards posed by unexploded wartime munitions and the logistical challenges they present to modern urban areas when uncovered during routine construction and development.