"Due to the need to defuse a World War II-era bomb, navigation has been restricted. Approaching the Swina river closer than 750 meters (0.5 miles) is restricted as well," the announcement read.
The Mk IV bomb was discovered in the bed of River Swina during state-sponsored commercial excavation. This type of bomb was apparently dropped over Poland by UK commandos during the war.
Polish specialists plan to lift the bomb to the water's surface, place it onto a specialized vessel and transfer it via the Swina river to a marine range where it will then be detonated. Additional security measures have been arranged in the town of Swinoujscie, through which the river runs.