UPDATE, 3:18 p.m.: The shooting was a murder-sucide, confirmed LAPD Chief Charlie Beck.
"The important thing for people to take away from this is the campus is now safe," Beck said at a news conference shortly after noon.
At least two people are dead and the UCLA campus is on lockdown after a shooting at the Los Angeles university on Wednesday, the university said, citing police.
The campus was placed on lockdown just after 10 a.m., and helicopter news footage showed students walking out of school buildings in a row with their hands above their heads.
Both victims are male, UCLA Police Chief Jim Herren said.
UCLA has asked those still on campus to shelter in an engineering building. The LAPD put the entire city on tactical alert and moved hundreds of officers to the campus and surrounding areas.
Bruin Alert: Shooting. Lock down continues for entire campus. Regardless of location on campus, go to secure location and deny entry
— UCLA Housing (@UCLAhousing) June 1, 2016
The Daily Bruin, the school's student newspaper, reported that the shooter was wearing a black jacket and black pants.
The university said in a statement posted online that police reported finding the two victims in Boelter Hall, a UCLA engineering building.
LAPD Capt. Andy Neiman said that he did not know the total number of victims or their conditions. It was not known if the university cited campus police or LAPD when it reported that two people were killed.
"The whole campus just started running, and I started running too," Mehwish Khan, a 21-year-old student who hid in the library with some other students, told the Los Angeles Times. "Everyone was very confused. We got in a building, and no one knew what was going on."
Rafi Sands, a 20-year-old student and vice president of the student government, told the Times that he and about 30 other students used belts to lock their classroom door. He said several conflicting accounts of the shooting began spreading via text messages and social media before people determined how serious the situation was.
"We get a lot of Bruin Alerts for small things," he said. "It took a while for everyone to realize this is serious."
Tom Fuentes, CNN's senior law enforcement analyst, said locking down a university the size of UCLA in an urban location is a "monumental task."
"If you want to search [a] four-bedroom house carefully enough to ensure, as if somebody's life depends on it, that nobody is in that house, it's going to take eight or nine SWAT officers an hour to do that," Steve Moore, a former FBI special agent, told LA TV station KTLA. "Now imagine a 10-story, 15-story building - whether they're classrooms or dorms - imagine also that you have to check every crawlspace, every overhead in the buildings."