At least three people have been killed and five people are in hospital after a shooting at a US university – with the gunman unaccounted for and the campus locked down.

Michigan State University Police described the suspect as a short black male in a cap, red shoes and a jean jacket.

They said some of those in hospital are in a life-threatening condition.

The incident began at around 8.18pm local time when shots were fired at Berkey Hall on the East Lansing campus.

Students and staff were told to “secure-in-place immediately” as officers responded to “multiple” 911 calls.

Police said the gunman then opened fire at the nearby university union and was last seen leaving the building on foot.

Large numbers are likely to be locked down as about 50,000 people attend the East Lansing campus – which also hosts evening classes.

A number of buildings have already been secured as police systematically search for the gunman.

The victims have been taken to Sparrow Hospital.

Chris Rozman, from Michigan State University Police, said “multiple” 911 calls had been received and that officers responded within minutes.

Lisa McClain, US representative for Michigan, tweeted: “There are reports of an active shooting on campus at Michigan State University.

“If you are there, police instructions are to Run, Hide, Fight. I am praying for all Spartans right now.”