LONDON (AP) — Police in southwest England said six people were killed, including the suspected shooter, in the city of Plymouth Thursday in a “serious firearms incident” that wasn't terror-related.

Devon and Cornwall Police said in a statement on Twitter that several other casualties were receiving treatment following the shooting. They declared a “critical incident” but did not provide details of what occurred in the Keyham district of the city. The area has been cordoned off.

“Police have confirmed that six people have died in the shooting in #keyham in #plymouth. More people are being treated for their injuries in hospital. Just so unspeakably awful," Plymouth Member of Parliament Luke Pollard tweeted.

Emergency services, including air ambulance and senior paramedics, responded to the incident at around 6:10 p.m. local time.

Officers found two women and two men dead, police said. Another man, believed to be the offender, was also dead at the scene. All are believed to have died from gunshot wounds. Another woman was treated at the scene for gunshot wounds, but died later in a hospital.

Johnny Mercer, one of Plymouth's lawmakers, said in a tweet the incident is “not terror related, and neither is the suspect on the run in Plymouth.”

Devon and Cornwall Police also said it was not terrorism related.