A 14-year-old boy has been charged with attempting to possess a Russian sub-machine gun and 100 rounds of ammunition with intent to endanger life.
A detective said she believed the teenager's intention was to intimidate another person after using the "dark web" in a bid to obtain the haul.
The teenager was detained in a police operation at the Riverside retail park, in Coleraine, Co Derry on Thursday morning.
He had allegedly handed over £150 for the ammunition to an operative, police said, believing he could further purchase a machine gun.
The offences are alleged to have occurred between 27 March and 7 April this year.
Covert evidence had been obtained and police said they were downloading his online interactions.
The accused appeared at Ballymena Magistrates' Court flanked by his father and three police officers.
