Berlin (AP) — German police said Tuesday that seven soldiers were injured after armored military vehicles crashed into each other on a Bavarian highway.

Several German media outlets reported that the vehicles involved in the crash on Monday belonged to the U.S. military, but German police said they were not authorized to give out information on the nationality of the injured soldiers.

The public affairs office for the U.S. Army Europe and Africa in Germany did not immediately return calls seeking confirmation.

Police in Amberg in southern Germany said that “a military convoy was driving on the A6 highway on maneuver duty, and that for still unknown reasons a rear-end collision involving four armored vehicles occurred.”

“According to initial findings, seven soldiers were injured and brought to hospital, two of them via rescue helicopter,” Tobias Mattes from Amberg police said in a statement, adding that one of the soldiers was in a serious condition.

The crash occurred at around 10:55 a.m. local time on the highway stretch between the Sulzbach-Rosenberg and Amberg-West junctions in the direction toward the Czech Republic.

The highway was blocked until the late afternoon.

Amberg is 40 kilometers (25 miles) south of the U.S. Army Garrison Bavaria in Grafenwoehr.