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Tech companies on Saturday expressed concerns over President Donald Trump's order to restrict migration from several countries, with leaders saying the move could directly impact their own staffers.

Silicon Valley's chieftans provided emotional support, as well as offers of legal assistance to employees affected by an executive order that banned all non-citizens from seven predominantly Muslim countries from entering the United States for at least 90 days.

The ban, which came only weeks after Trump sat down with Silicon Valley's top executives to express support for their innovation efforts, extends to workers who have visas and green cards and are currently out of the country.

In an internal memo obtained by CNBC, Apple CEO Tim Cook told employees, "There are employees at Apple who are directly affected by yesterday's immigration order. Our HR, Legal and Security teams are in contact with them, and Apple will do everything we can to support them."

Cook concluded by quoting Dr. Martin Luther King: "We may have all come on different ships, but we are in the same boat now."

Executives from Microsoft, Google, Netflix, and Y Combinator, as well as educators at MIT and Carnegie Mellon, were among technology leaders who condemned President Donald Trump's wide-reaching order. The decision effectively blocks travelers from Syria, Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen.

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Brad Smith, Microsoft's president and chief legal officer wrote on LinkedIn that there are 76 Microsoft employees from the 7 countries who have work visas, and are affected by the new order. It is offering those employees legal support regarding immigration.

"We share the concerns about the impact of the executive order on our employees from the listed countries, all of whom have been in the United States lawfully, and we're actively working with them to provide legal advice and assistance," Microsoft told CNBC.

Facebook also told CNBC that it was assessing how to protect its workers from adverse effects.

Meanwhile, Google CEO Sundar Pichai said in a memo to employees that nearly 200 employees abroad would be affected by the move. "We're concerned about the impact of this order and any proposals that could impose restrictions on Googlers and their families," a spokesperson said in a statement released to CNBC.

Facebook CEO Mark Zuckerberg was one of the first to address the ban publicly. "We need to keep this country safe, but we should do that by focusing on people who actually pose a threat," Zuckerberg wrote on Facebook on Friday.

Netflix CEO Reed Hastings wrote on Facebook that "Trump's actions are hurting Netflix employees around the world, and are so un-American it pains us all. Worse, these actions will make America less safe (through hatred and loss of allies) rather than more safe."

Airbnb co-founder and CEO Brian Chesky also advocated for "open door" policies said that

Open doors brings all of US together. Closing doors further divides US. Let's all find ways to connect people, not separate them. — Brian Chesky (@bchesky) January 28, 2017

Uber told CNBC that it had 12 employees affected by the order, and is offering legal support. In an internal memo, Uber CEO Travis Kalanick also pointed out that the ban affects "thousands" of Uber drivers who "take long breaks to go back home to see their extended family."

Sam Altman, president of prestigious start-up program Y Combinator, called on tech leaders to take action, writing in a blog post on Saturdaythat "it is time for tech companies to start speaking up about some of the actions taken by President Trump's administration."

Slack boss Stewart Butterfield tweeted that America is "throwing away" its moral authority with the ban. "Immigration is unambigously an economic benefit, but, doesn't matter: [D]o the right thing because it's right," Butterfield tweeted.

"And he's just getting started." • It's still so hard to believe that this is real life. Nearly every action seems gratuitously … evil. https://t.co/ZcpdeUnlYf — Stewart Butterfield (@stewart) January 28, 2017

Anil Dash, CEO of Fog Creek Software, which helped create products like StackOverflow and Trello, called for more action from the technology community.

It's time for leaders at Facebook, Google, Apple, Microsoft who were at that Trump roundtable to step up. You've done it for crises before. — Anil Dash (@anildash) January 28, 2017

MIT said that the ban was already affecting international students, and Carnegie Mellon engineering professor and frequent tech industry commentator Vivek Wadhwa said that it was courageous for Butterfield to make a statement.

"Why is not every other tech executive — and human being?" he tweeted.

Letter to the MIT community regarding Executive Order affecting international students and scholars: https://t.co/ys4o3EeYNB pic.twitter.com/J2CZLeKaeS — MIT (@MIT) January 28, 2017

This shows courage. CEO of Slack speaking up. Why is not every other tech executive--and human being? https://t.co/CsOvEHz6hh — Vivek Wadhwa (@wadhwa) January 28, 2017

As the day wore on, many other tech leaders chimed in:

When we close our hearts & stop loving other people as ourselves (MK 12:31) we forget who we truly are---a light unto the nations. #noban — Marc Benioff (@Benioff) January 28, 2017

On every level -moral, humanitarian, economic, logical, etc.- this ban is wrong and is completely antithetical to the principles of America. — Aaron Levie (@levie) January 28, 2017

The Executive Order's humanitarian and economic impact is real and upsetting. We benefit from what refugees and immigrants bring to the U.S. https://t.co/HdwVGzIECt — jack (@jack) January 28, 2017

This article first appeared on CNBC.com