WARSAW, Poland (AP) — Historians in southern Poland say they have uncovered wreckage of a World War II bomber used by the Soviet air force before the plane was downed 75 years ago.

Parts of the U.S.-made B-25 Mitchell and human remains were found Sunday in woods near the town of Bierun where witnesses reported seeing the plane come down on Jan. 19, 1945.

The remains of four people and pieces of Soviet uniforms were among the wreckage, the regional history museum said on its Facebook page.

Explorers started looking for the plane shortly before the anniversary of the downing. After Sunday's discovery, the excavation work was suspended and the site was sealed off by police, the Silesia history museum said.

Local historians, based on witness testimony and records, say the plane was on a mission of bombing a railway junction near Ostrava, now in the Czech Republic, when it was downed by a German fighter.

The Soviet air force had 861 B-25 bombers. The United States made military aircraft available to Allied nations in the fight against Nazi Germany during World War II.