LONDON (AP) — French police have arrested a dozen people, including a U.K. border officer, in an investigation into a crime group suspected of running drugs and firearms.

Britain's National Crime Agency said Monday the police detained the 36-year-old officer near Calais along with three other British citizens on Friday. They remain in custody. Authorities say 11 guns were seized, together with 34 kilograms (75 pounds) of cocaine and seven kilograms (15 pounds) of heroin.

Soon after, the London police force's organized crime division arrested eight others in Kent in southeast England. Six were charged with conspiracy to import firearms and class A drugs. The two others were released under investigation.

Dave Hucker of the NCA says the investigation is ongoing in Britain and in France.