A backpack caught on fire in a Boelter Hall classroom Wednesday, causing hundreds of students throughout the building to evacuate. 

Around 12:30 p.m., a backpack began to catch fire in Boelter Hall room 5249, where a bioengineering class was taking place, said Jeeth Pawar, a third-year bioengineering student in the class. Students in Boelter evacuated soon after, and an alarm later began to sound, he said, adding that some smoke began to seep into the hallways.

In an emailed statement, UCLA Fire confirmed the backpack was the source of the fire, but the exact cause remains unclear and is currently under investigation. UCLA Fire said it responded to an alarm activation in Boelter, and evacuation was already in progress as they arrived. However, building management was able to put the fire out before officials arrived on site, according to the statement.

Damages are being evaluated, but no injuries have been reported.