EW Sparrow Hospital is treating five victims of the shooting in its emergency room, a spokesperson told CNN.
He did not provide information on the severity of their injuries. A university spokesperson confirmed the three fatalities.
Campus police said they are searching for one suspect.
He is described as a short man with red shoes, a denim jacket and cap.
The suspect was reported to be on foot.
All classes, athletics and campus-related activities at MSU are cancelled for 48 hours, MSU police said as officers in tactical gear swarmed the university.
“Please DO NOT come to campus tomorrow,” they said.
Police reported shots fired near Berkey Hall on the East Lansing campus around 8.30pm local time (12.30pm AEDT), telling the campus community in a tweet to “please secure-in-place immediately.”
About an hour later, campus police reported “there is another reported shooting at IM East”.
“It appears there is only one suspect at this time,” MSU police said.
IM East is a campus fitness centre about 1.5km away from Berkey Hall, where police first reported shots were fired.
Michigan Governor Gretchen Whitmer said she is being briefed on the shooting at the university.
“I’ve been briefed on the shooting at Michigan State University. The Michigan State Police along with @msupolice, local law enforcement and first responders are on the ground,” the governor tweeted.
“Let’s wrap our arms around the Spartan Community tonight.
“We will keep everyone updated as we learn more.”
The Bureau of Alcohol, Tobacco, Firearms and Explosives in Detroit also tweeted that it’s “responding to an active shooter” at the university.
Special agents from the FBI are also responding to assist, a spokesperson from the bureau’s Detroit office tells CNN.
Around 10.10pm local time (2.30pm AEDT), police tweeted that Berkey Hall and other several campus buildings were cleared, including Brody Hall, Snyder/Phillips Hall, Mason Hall, Abbot Hall, Landon Hall and the MSU Union.
MSU student Nithya Charles told CNN she was sheltering in place within a lounge area at Campbell Hall – the campus’ student union – on the north side of campus.
“We’re not learning very much so much,” Charles told CNN’s Erin Burnett, explaining that she’s sheltering with about 30 other people.
She said she did not hear any gunshots herself, but said some of her co-workers heard shots.
“Everyone is obviously kind of stressed, but seems to be calm now,” Charles said.
