Police had to kill a man who crashed a car into a group of people before slashing at several others on the campus of Ohio State University Monday morning.
In total, 10 people were taken to nearby hospitals to be treated for stab wounds and injuries related to the car crash.
The so-far-unidentified assailant jumped a curb at about 9:52 and hit several pedestrians.
Police said he was armed with a butcher's knife and began slashing at other passersby.
“Our officer ended the situation in less than a minute," Police Chief Craig Stone said.
The suspect was declared "dead on arrival."
“There were rumors of a second suspect. We believe it was one suspect," Stone added.
A campus wide alert was sent at 9:55 a.m. warning the community of an "active shooter."
The shots heard were from the responding officer who killed the suspect.
The campus was placed on lockdown for about an hour as scores of officers, including federal law enforcement, scoured the campus for a possible second suspect.
The lockdown was lifted at about 11 a.m.
WARNING: Images and videos in this developing, breaking news story may be considered too graphic for some viewers.
This is a breaking news story. Refresh for updates.
An alert from Ohio State University warned of an active shooter on campus, near Watts Hall at West 19th Avenue and College Road. At least nine people were taken to the hospital, according to the Columbus Fire Department.
The scene was secured and the campus-wide lockdown lifted by 11:30 a.m. ET.
A federal law enforcement official told CNN the attacker used a car to target a group of students before crashing into a planter.
The official also said the suspect began chasing people with a knife and had a "crazy look in his eye." The gunshots heard on-campus were from responding officers.
Officials believe at least one assailant was killed. Social media users near the scene of the incident reported heavy police activity near the campus's Lane Garage. Two people were taken from the garage in handcuffs, according to local reports.
“I heard two or three shots and I was grabbed by some guy who said ‘get in the building’ and I’ve been here ever since," Andrew Hinton, an Ohio State student, told CNN. “There are cops circling a dining hall with weapons drawn.”
The Columbus Fire Department confirmed at least nine people were taken to a nearby hospital to be treated for injuries. Two of the injured were listed in "stable condition." Officials did not immediately provide updates for the remaining five victims. It is also unknown exactly what caused their injuries.
At least six trauma surgeons were requested at Ohio State University Wexner Medical Center, according to WSYX/WTTE.
The message to students and faculty included a warning to "run, hide or fight."
Much of the campus was locked down as police conducted a search. The lockdown lasted for almost two hours and all classes were canceled for the remainder of the day, according to Ohio State Emergency Management.
The area around 19th and College Avenue as well as some buildings on campus remained closed pending the investigation.
A reporter with "The Lantern" the university's student-run newspaper said, "there's at least one body bag present in front of Koffolt Labs."
Police established a crime scene by 10 a.m., about 20 minutes after the alert went out to students.
Wyatt Crosher, an Ohio State student, told CNN he and his friends heard what they believed to be gunshots.
“They did come in quick succession from where we were we could hear faint pops and when the ambulances came we assumed they were gunshots," he said.
Brianna O'Dell, another university student, said her class was placed on lock-down.
"Be safe and stay inside everyone," she wrote on Facebook. "My class is in a closet on lock down [right now]. Take shelter and please don't go outside especially on North campus.
Ohio Gov. John Kasich said on Twitter, "Ohio's thoughts and prayers go out to the Ohio State community. Be safe, listen to first responders."
This story will be updated.