A man has been arrested at Los Angeles International Airport who, officials say, was carrying weapons in his luggage and wearing a bulletproof vest.
Yongda Huang Harris, a US citizen, had arrived from Japan and was due to board a flight to Boston when he was stopped.
Border officials said a number of items were found including knives, handcuffs, body bags and a smoke bomb.
He was charged with transporting hazardous items – an allegation relating to the smoke bomb.
“He was detained by customers border protection because he was wearing a full ballistic vest with a trauma plate and knee pads and to them that was unusual,” Commander Blake Chow of the Los Angeles police department told ABC.
“He had a myriad of items in his checked-in luggage and it raised a lot of suspicion.”
Mr Harris, a 28-year-old man from Boston, was also said to be wearing flame-resistant trousers. Other items found included a hatchet, a collapsible baton, a bio-hazard suit, a gas mask, leg irons and lead-filled truncheons.
Officials said he had recently been living and working in Japan but was not co-operating with investigators attempting to question him.
They also gave no explanation of how he was able to board his flight in Japan without raising suspicions.