WARSAW, Poland — Polish police say they are evacuating more than 2,000 people after the discovery of an unexploded World War II-era bomb weighing some 250 kilograms (550 pounds).

The bomb was discovered in the Oder River in the town of Glogow, an area of southwestern Poland that was part of Germany during the war.

Lukasz Szulikowski, an official with the Glogow police, told the PAP news agency that authorities are evacuating some 2,000 to 3,000 people in the area by bus to a nearby school ahead of the removal of the bomb.

He said the bomb was discovered during the cleaning of the river bottom.

The private broadcaster TVN24 reported that it is the fourth World War II-era bomb found in the region over the past year.