A 45-year-old man has been arrested after six people were shot dead in separate attacks in the US state of Michigan.

Officials corrected an earlier report of seven dead, stating that one of the victims was alive but seriously injured.

The suspect was apprehended 5.40am Irish time after the shootings last night in the city of Kalamazoo, police said.

Michigan state trooper Lieutenant Dave Hines told a press conference that there were three separate shootings – one outside an apartment complex, another outside a car dealership, and the third at a chain restaurant.

"What it looks like is we have somebody driving around, finding people and shooting them dead in their tracks," Kalamazoo County Undersheriff Paul Matyas told the local CNN affiliate 24 Hours News 8.

"This is your worst nightmare, when you have somebody just driving around randomly killing people," he added.

At a later press conference Kalamazoo County Prosecutor Jeff Getting identified the white male suspect as Jason Brian Dalton and said he will face murder charges in court tomorrow.

Mr Getting said Mr Dalton is accused of shooting eight people, six of whom died.

Earlier reports of the death of seventh victim, a teenage girl, were incorrect, Mr Getting said, though he did say that she was "gravely injured".

The gunman's motives were unclear, officials said.

The suspect was armed when he was arrested at a traffic stop, but surrendered peacefully, Mr Matyas said.

Kalamazoo is located some 190km west of the industrial city of Detroit and has a population of 76,000, according to census figures.

The Kalamazoo killings follow a pattern of mass shootings in the US that include the 2 December massacre in San Bernardino, California that left 14 people dead and 22 wounded, and the 14 December, 2012 Sandy Hook school massacre in which 20 children and six adults were shot dead.

Gun violence kills about 30,000 Americans every year and mass shootings - rare in most countries - have been on the rise in the US.

According to the tracking website gunviolencearchive.org, there were 330 mass shootings in the United States in 2015, up from 281 in 2014.

They affected nearly every part of the country, reaching into both big cities and small towns.