The robbers rode a motorbike to the Kim Phat Dung gold shop on Vinh Loc Road, Vinh Loc Commune, Binh Chanh District, and said they wanted to exchange currency, a service informally provided by many gold shops in the country.
One of them opened a bag, took out a pepper spray and sprayed the owner, while the other used a hammer to smash the shop's glass cabinets.
They escaped with several hundred million dong (VND100 million = $4,300) worth of gold and jewelry, leaving behind the hammer, the pepper spray and a scimitar.
Police are investigating the incident using images of the men caught on camera.
On April 20, a man holding a handgun attempted to rob a Techcombank branch in Hanoi's Soc Son District.
The man, later identified by the police as Tran Huu Trung, came into the bank, pointed the gun at employees and threatened them. When an employee pressed the alarm button, he ran out. No one was injured and no money was lost in the attempted robbery.
Trung, 29, surrendered to the police on April 25.