Mark Zuckerberg came out against President Trump’s executive orders on immigration policy in a lengthy post on his Facebook page Friday.

“Like many of you, I’m concerned about the impact of the recent executive orders signed by President Trump,” Zuckerberg said, referencing the orders Trump signed earlier this week to build a wall along the U.S.-Mexican border and prioritize the deportation of undocumented immigrants from so-called sanctuary cities in the U.S.

“We need to keep this country safe, but we should do that by focusing on people who actually pose a threat,” the Facebook CEO continued. “Expanding the focus of law enforcement beyond people who are real threats would make all Americans less safe by diverting resources, while millions of undocumented folks who don’t pose a threat will live in fear of deportation.”

While he was critical of Trump’s stance on immigration during the presidential campaign, Friday’s post is the first time that Zuckerberg has publicly addressed the president’s policies since the inauguration. His comments also come one day after Facebook COO Sheryl Sandberg voiced her opposition to Trump’s anti-abortion executive order.

In his post on Friday, Zuckerberg said he remained optimistic about Trump’s vague commitment to protecting “Dreamer” immigrants who were brought into the U.S. at a young age from deportation.

“I’m also glad the President believes our country should continue to benefit from ‘people of great talent coming into the country,'” Zuckerberg said. Trump has proposed a “merit-based” immigration policy that he’s said will directly benefit tech companies like Facebook that already rely on being able to hire skilled workers from other countries.

Zuckerberg has been an immigration reform activist for years, dating back to his cofounding of the FWD.us lobbying group in 2013. Despite recent speculation that Zuckerberg is interested in getting into government, the billionaire was noticeably absent from Trump’s recent meeting with tech CEOs.

Here’s Zuckerberg’s full post on Trump’s immigration orders from Friday:

My great grandparents came from Germany, Austria and Poland. Priscilla’s parents were refugees from China and Vietnam. The United States is a nation of immigrants, and we should be proud of that.

Like many of you, I’m concerned about the impact of the recent executive orders signed by President Trump.

We need to keep this country safe, but we should do that by focusing on people who actually pose a threat. Expanding the focus of law enforcement beyond people who are real threats would make all Americans less safe by diverting resources, while millions of undocumented folks who don’t pose a threat will live in fear of deportation.

We should also keep our doors open to refugees and those who need help. That’s who we are. Had we turned away refugees a few decades ago, Priscilla’s family wouldn’t be here today.

That said, I was glad to hear President Trump say he’s going to “work something out” for Dreamers — immigrants who were brought to this country at a young age by their parents. Right now, 750,000 Dreamers benefit from the Deferred Action for Childhood Arrivals (DACA) program that allows them to live and work legally in the US. I hope the President and his team keep these protections in place, and over the next few weeks I’ll be working with our team at FWD.us to find ways we can help.

I’m also glad the President believes our country should continue to benefit from “people of great talent coming into the country.”

These issues are personal for me even beyond my family. A few years ago, I taught a class at a local middle school where some of my best students were undocumented. They are our future too. We are a nation of immigrants, and we all benefit when the best and brightest from around the world can live, work and contribute here. I hope we find the courage and compassion to bring people together and make this world a better place for everyone.