US federal authorities have confirmed a US man stole the thumb of a Chinese terracotta warrior statue being displayed at a Philadelphia museum late last year.

According to the arrest affidavit, 24-year-old Michael Rohana made his way into the museum's special exhibit on the Terracotta Warriors and appeared to break something off from the Cavalryman's left hand. He then put it in his pocket, and left. He is being charged with theft of a major artwork from a museum, concealment of major artwork stolen from a museum and interstate transportation of stolen property.