Facebook boss Mark Zuckerberg said he's "concerned" by the recent executive orders US President Donald Trump signed to restrict immigration.

Zuckerberg said the US should remain open for refugees and not target people who don't pose a threat, such as undocumented immigrants who came with their parents at a young age. He and his wife, Priscilla Chan, are descendants of immigrants and refugees, he wrote in a Facebook post Friday.

"We need to keep this country safe, but we should do that by focusing on people who actually pose a threat," Zuckerberg said. "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."

Zuckerberg repeated some of Trump's more pro-immigrant quotes, striking a conciliatory tone and saying he was glad to hear Trump say he would "work something out" for Dreamers – immigrants who came to the US at a young age – and "people of great talent coming into the country."

The post was Zuckerberg's strongest political comment since Trump's inauguration, at a time when technology leaders are trying to adapt to the new administration and its planned changes.

Trump has taken strong anti-immigrant stances after running a campaign focused on limiting Muslim refugee access to the US and building a wall to border Mexico.

On Friday, the president signed an executive action to establish new vetting procedures for some people seeking to enter the US, saying the measure would prevent terrorists from being admitted.