ZAGREB, Croatia (AP) — Croatian authorities on Sunday destroyed a huge anti-ship mine from World War II that was buried in the seabed near a key northern Adriatic Sea port.

Local authorities in the port of Rijeka sounded emergency sirens early on Sunday to mark the start of the operation. They earlier had evacuated parts of the city while also halting all traffic to secure the area during the removal of the bomb with 690 kilograms (1,500-pounds) of explosives.

Officials said that the mine, which was first discovered last June, was positioned too close to the city and that it had to be moved further away before emergency teams could perform the controlled detonation.

Videos released by Croatian police after the operation was completed on Sunday showed the mine at the bottom of the sea, and divers strapping it up so it could be moved. Another video showed a huge explosion further away, sending seawater high up in the air.

Police officer Nenad Krasny said the mine was very dangerous and contained huge quantities of explosives. He added that 24 people took part in the operation, and that great care was taken to remove the mine from the port “because anything else would be too dangerous for the citizens and infrastructure.”