Some of the tech industry’s most prominent CEOs have come forward over the past day to denounce President Donald Trump’s policy of separating children from their parents who are arrested at the border. Apple CEO Tim Cook, Facebook CEO Mark Zuckerberg, and Tesla CEO Elon Musk are among the CEOs who have called for an end to the policy, which has also been criticized by the United Nations as “unconscionable.”

Cook said the separations are “inhumane and need to stop,” telling The Irish Times: “It’s heartbreaking to see the images and hear the sounds of the kids. Kids are the most vulnerable people in any society. I think that what’s happening is inhumane. It needs to stop.”

In a Facebook post, Mark Zuckerberg said, “We need to stop this policy right now.” He started a fundraiser for the Texas Civil Rights Project, which raised about $17,000 in its first few hours. In response to a question from a user about why he didn’t donate more, Zuckerberg responded: “I’ve invested a lot in this issue — both money and time. Many people want to know how they can help too. This is a good way to get involved.”

Airbnb CEO Brian Chesky led the way on Monday.

Several other prominent tech CEOs protested the policy on Twitter, starting with Twitter CEO Jack Dorsey:

Google CEO Sundar Pichai:

YouTube CEO Susan Wojcicki:

Uber CEO Dara Khosrowshahi:

Yelp CEO Jeremy Stoppelman:

Lyft CEO John Zimmer: