A man who injured 11 people, one critically, in a rampage at Ohio State University was of Somali descent and a student on campus, say US officials.
Abdul Razak Ali Artan, 18, rammed his car into a group of pedestrians at the college then got out and began stabbing people before police shot him dead.
Police Chief Kim Jacobs said they were investigating whether Monday morning's incident was a terrorist attack.
The FBI joined the inquiry at the 60,000-student campus in Columbus.
Artan was a Somali refugee who was living in the US as a legal permanent resident, US media report.
Asked at a news conference whether it could have been a terrorist act, Police Chief Jacobs said: "I think we have to consider that it is."
She added: "Obviously with the purposeful intent that was noticed - driving on the sidewalk - we're going look at it from the potential that it was planned."
Artan studied logistics management in the college of Business at Ohio State, reports the Columbus Dispatch.
The incident began at 10:00 local time on Monday when a vehicle jumped the kerb at the campus, striking pedestrians near Watts Hall, the science and engineering building.
Ohio State Police Chief Craig Stone said the driver got out of the vehicle and began stabbing bystanders with a "butcher's knife".
A policeman who was nearby because of a gas leak shot the driver dead in less than a minute.
Authorities identified the officer as 28-year-old Alan Horujko, who has been with Ohio State University police since 2015.
The injured included a mix of academic faculty, maintenance staff, and graduate and undergraduate students.
Campus police say that CCTV cameras filmed the suspect arriving on campus alone, indicating that he did not have an accomplice aiding him during the attack.
Student Martin Schneider said he heard the car's engine revving.
"I thought it was an accident initially until I saw the guy come out with a knife," he said.
The college had warned students in a tweet to "Run Hide Fight", warning there was an "active shooter", though authorities later said the attacker did not use a firearm.
Hours later police declared the scene "secure", lifting the shelter-in-place order and cancelling classes for the remainder of Monday.
Columbus Police sent a SWAT team, dog units, negotiators and a helicopter to the scene.
Federal officials from the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives also responded.
In recent months, federal officials have warned about extremist efforts to recruit people for knife and car attacks, which are seen as easier for home-grown radicals to carry out than bombings.
The Islamic State group has urged sympathisers to use whatever weapons are available to them to carry out attacks.
It also called on followers to use vehicles to attack the Thanksgiving Day parade in New York City over the weekend.
Public school districts near to Ohio State placed their students on lockdown during Monday's alert.
The attack came just as students were resuming classes following the Thanksgiving holiday, and after the university's American football team defeated rival Michigan in a match that drew over 100,000 people to the Columbus campus on Saturday.