A 15-year-old boy from Formby in Merseyside has been arrested on suspicion of importation of a firearm.
As part of their investigation police say they recovered a handgun which had been ordered from the United States and was destined for delivery to a property in Formby.
"Working together with UK Border Force we were able to stop the weapon from reaching its final destination. Our message to those involved in gun crime is clear, we are relentless in our pursuit of those who use firearms on our streets."
The boy has been questioned and released on police bail pending further inquiries.
More top news
Former Liverpool and Newcastle defender Jose Enrique has revealed he has had surgery to remove a rare brain tumour and is now in recovery.
The mother-of-two said she was told by RSPCA investigators they were looking at the possibility that poison-laced sausages were involved.
The Beatle made several stops during his trip through Liverpool with James Corden and shocked many Scousers along the way.