A gunman has killed at least 18 people and injured 13 in the town of Lewiston, Maine, after bursting into a bowling alley and a bar and opening fire with an AR 15-style rifle last night.

The town is on lockdown as police hunt for suspect Robert Card, a 40-year-old US Army reserve firearms instructor who was hospitalized this summer for two weeks with mental health issues.

Officers have confirmed that Card's vehicle - a 2013 white Subaru - was found near the boat dock in Lisbon, about seven miles southeast of Lewiston, but the suspect was not inside. 

Chilling CCTV images show the shooter pointing his rifle as he walked into the Sparetime Recreation bowling alley, while dramatic footage shows terrified people running for their lives. Residents have been told to lock their doors.

Card, from Bowdoin, Maine, had previously reported hearing voices and had threatened to shoot up his National Guard base in Saco, Maine, according to the Maine Information and Analysis Center - a division of the Maine state police.  

The 'armed and dangerous' shooter, who has been named as a 'person of interest' by police, was holding an AR 15-style rifle with a laser optic when he burst into the bowling alley at 7:15pm local time (12.15am BST) to begin his rampage. 

Police then received calls about a shooting at a second location, Schemengees Bar and Grille, which was around four miles away. This is the deadliest attack of the 565 mass shootings in the US this year.