Police in Hanoi are investigating a local man who was found on Sunday to possess guns, bullets and knives, news website VietNamNet has reported.
Nguyen Van Quang, 61, was found sitting in a parked car with three knives, and two guns loaded with five bullets. Six unloaded bullets were also found in the car.
Possessing firearms is illegal in Vietnam.
The car was parked in front of a barber shop on Tran Khat Chan Street.
Hanoi police are also investigating the origin of three guns, including one exclusively made for military purposes, found at a local guest house last week where police arrested several groups of alleged drug dealers.
The guns' owner has been identified as Tran Long Son, 21, who was also found with a gun and bullets at his house in nearby Nam Dinh Province.
Son said he bought the guns in Hai Phong for VND7.5 million each. He said he had planned to resell them later.