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.

Brian Krzanich, Intel’s (INTC) CEO, called upon Trump to be more forceful in his remarks when he weighed in on Twitter. The 57-year-old chief executive announced in a company blog post on Monday evening he had also resigned from Trump’s manufacturing council.

Not everyone in tech was as harsh on Trump, however. Salesforce.com CEO Marc Benioff took a more generous approach, thanking Trump for eventually taking a more severe stance.

But perhaps it was Facebook COO Sheryl Sandberg who was most poignant, taking to Facebook (FB) to explain how the events in Charlottesville left Sandberg “heartbroken.” She also explained the challenges in explaining the events in Charlottesville to her 10-year-old daughter.

“How do you tell a 10-year-old that such extreme racism and inhumanity has taken place so recently?” Sandberg wrote. “And how do you explain why atrocities are still committed against so many people all over the world?”

(Additional reporting by Julia La Roche.)

Updated at 11:31 p.m. ET on August 14, 2017 to reflect Krzanich’s resignation from Trump’s manufacturing council on Monday evening.

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JP Mangalindan is a senior correspondent for Yahoo Finance covering the intersection of tech and business. Email story tips and musings to [email protected]. Follow him on Twitter or Facebook.

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