An OMON riot police officer was arrested Monday in a sting operation while trying to sell explosives and ammunition that he purportedly stole from the arms depot he was tasked with overseeing, police and prosecutors said.

Mikhail Belikov, 56, was detained by police after selling various explosive devices and ammunition for 152,000 rubles ($5,000) to an undercover agent, the Investigative Committee said in a statement.

Police subsequently found Belikov's personal cache of stolen weapons, which included more than 4,300 rounds of ammunition, more than 350 detonating fuses and two grenades, among other explosives, the committee said.

"The suspect has served in the OMON police at least 20 years, and his post allowed him to have total access to the arms," Moscow police spokesman Viktor Biryukov told Interfax.

The Khoroshevsky District Court on Monday sanctioned Belikov's arrest pending the criminal investigation, Interfax said. He is being investigated on suspicion of weapons trafficking and abuse of his position.

Belikov's arrest comes just weeks after officer Denis Yevsyukov, head of a police precinct in southern Moscow, shot three people dead and wounded six others in a supermarket rampage last month. Yevsyukov, who was apprehended following the attack, used a stolen gun in the shooting spree.