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.

Ripping children from their parents’ arms is cruel. This policy must end. pic.twitter.com/R2b3FXtxqU — Brian Chesky (@bchesky) June 18, 2018

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

Do everything it takes to #KeepFamilesTogether.



What are the highest impact ways to help? — jack (@jack) June 19, 2018

Google CEO Sundar Pichai:

The stories and images of families being separated at the border are gut-wrenching. Urging our government to work together to find a better, more humane way that is reflective of our values as a nation. #keepfamiliestogether — Sundar Pichai (@sundarpichai) June 19, 2018

YouTube CEO Susan Wojcicki:

Regardless of your politics, it's heartbreaking to see what's happening to families at the border. Here are some ways you can help: https://t.co/IFVG6g8AKO — Susan Wojcicki (@SusanWojcicki) June 19, 2018

Uber CEO Dara Khosrowshahi:

As a father, a citizen and an immigrant myself, the stories coming from our border break my heart. Families are the backbone of society. A policy that pulls them apart rather than building them up is immoral and just plain wrong. #KeepFamiliesTogether https://t.co/g2Cu40zvcX — dara khosrowshahi (@dkhos) June 19, 2018

Yelp CEO Jeremy Stoppelman:

I hope others from SF/Bay Area tech companies will join me at this march planned June 30. Please also consider donating to one of these great orgs assembled by @dahlialithwick & @mjschlanger: https://t.co/mSiMtgw9ga #FamiliesBelongTogether https://t.co/E5jXu4OSiv — Jeremy Stoppelman (@jeremys) June 19, 2018

Lyft CEO John Zimmer: