The news agency Reuters reported Saturday that the U.S. military believes that unarmed U.S. Africa Command remotely piloted aircraft (RPA) reported lost over Tripoli, Libya, Nov. 21 was in fact shot down by Russian air defenses and it is demanding the return of the aircraft’s wreckage.

U.S. Army General Stephen Townsend, who leads Africa command, said he believed the operators of the air defenses at the time “didn’t know it was a U.S. remotely piloted aircraft when they fired on it.”

“But they certainly know who it belongs to now and they are refusing to return it. They say they don’t know where it is but I am not buying it,” Townsend told Reuters in a statement, without elaborating.

The U.S. assessment, which has not been previously disclosed, concludes that either Russian private military contractors or Haftar’s so-called Libyan National Army were operating the air defenses at the time the drone was reported lost on Nov. 21, said Africa Command spokesman Air Force Colonel Christopher Karns.

Early, the U.S. Africa Command noted that RPA operations are conducted in Libya to assess the ongoing security situation and monitor violent extremist activity.

These operations are critical to counter terror activity in Libya and are fully coordinated with appropriate government officials.