Google fired 28 employees in connection with sit-in protests at two of its offices this week, according to an internal memo obtained by The Verge. The firings come after 9 employees were suspended and then arrested in New York and California on Tuesday.

In a memo sent to all employees on Wednesday, Chris Rackow, Google’s head of global security, said that “behavior like this has no place in our workplace and we will not tolerate it.”

He also warned that the company would take more action if needed: “The overwhelming majority of our employees do the right thing. If you’re one of the few who are tempted to think we’re going to overlook conduct that violates our policies, think again. The company takes this extremely seriously, and we will continue to apply our longstanding policies to take action against disruptive behavior — up to and including termination.”