Two men have been killed at the University of California in Los Angeles (UCLA), in what authorities say appears to be a murder-suicide shooting.
UCLA Police Chief James Herren told the Los Angeles Times that it's possible that one of the victims is the shooter.
The campus was placed on lockdown around 10am local time (5am NZ time). People took shelter in an engineering building as hundreds of armed police officers and FBI agents swarmed the university and surrounding streets.
Student Carrie Rapaport live tweeted the ordeal, and posted a picture of her and other students using their belts to lock a door.
In another tweet, Ms Rapaport sent her love to her family and friends and asked them not to phone, as it would be inappropriate to talk.
Helicopter news footage showed students walking off the campus with their hands above their heads.
Bioengineering student Bahjat Alirani said police were yelling at people to run from the scene.
"I was in Boelter Hall to take a final and I exit the staircase to see SWAT-looking police yelling at everyone to evacuate immediately," Alirani told Reuters.
"I check my email and BruinAlert had immediately sent an email to all students notifying them of a shooter in the engineering building."
The Daily Bruin says the shooter was wearing a black jacket and pants.
UCLA is in the Westwood area of Los Angeles and has around 43,000 students enrolled.