This is a developing story. Please check back for updates.

UPDATE: 1:05 p.m. EDT – Security allowed everyone to reenter the room shortly after everyone was evacuated from Thursday’s FCC net neutrality vote.

Security dogs swept the room before anyone could reenter, according to a live video feed. It remained unclear what caused the evacuation.

Original story:

An unidentified security threat caused an evacuation of Thursday's Federal Communications Commission (FCC) meeting to vote on net neutrality. Those present said they were told by security to leave the room.

"On advice of security, we need to take a brief recess," said FCC Chairman Ajit Pai

The meeting began Thursday morning to vote on whether to repeal net neutrality protections, a controversial decision that caused contention between supporters and detractors. Everyone in the room was told to leave.

"Told to leave everything until room was cleared by security," New York Times technology reporter Cecilia Kang tweeted. "Now more than 100 people outside the meeting room, standing in halls of FCC waiting."

Security reportedly took all five commissioner's phones from their desks.

The meeting was taking place in Washington, D.C. It remained unclear what caused the evacuation or what the specific security threat was. The net neutrality vote caused potential security threats earlier Thursday as well, when online hactivist organization Anonymous threatened to carry out a "destructive cyber attack on the FCC.

"Anonymous will continue its cyber attack on the FCC for the entire day in response to net neutrality vote," a Twitter account associated with the group said.