The driver of a vehicle was arrested and one AK-47 rifle and a pistol were seized from his car at Rambi near here.
The vehicle was going to Gangtok from Siliguri, the police said.
An AK-47 rifle which was concealed in its trunk, a 9 mm pistol and Rs 1.05 lakh were seized from the car, the police said.
When the vehicle tried to escape, the police chased it and caught the driver, sources said.