Silicon Valley reacted swiftly to violence that erupted Saturday between white nationalists and counter-protesters in Charlottesville, Virginia, which left at least one dead and dozens more injured.

Apple CEO Tim Cook did not mince words on Twitter (TWTR), calling the violence a “moral issue.”

Airbnb CEO Brian Chesky told Yahoo Finance in a statement that Airbnb removed several rally participants from the service who had booked places to stay in Charlottesville and planned on holding a series of parties at those Airbnb bookings.

“We require those who are members of the Airbnb community to accept people regardless of their race, religion, national origin, ethnicity, disability, sex, gender identity, sexual orientation, or age,” Chesky said in the statement. “When we see people pursuing behavior on the platform that would be antithetical to the Airbnb Community Commitment, we take appropriate action.”

Other leaders in tech also took to social media to express their anger and sadness, including T-Mobile CEO John Legere and Box CEO Aaron Levie, who applauded Merck CEO Kenneth Frazier’s decision to resign from President Donald Trump’s American Manufacturing Council.

Trump came under fire over the weekend for initially blaming Saturday’s violence on “many sides” without calling out white nationalists by name — a move he attempted to rectify with a stronger statement on Sunday.