Silicon Valley leaders immediately expressed concern and denounced an executive order signed on Friday by U.S. President Donald Trump that temporarily banned immigrants from seven predominantly Muslim countries from entering the United States, even if they already were approved to do so. However this ban was temporarily overturned on Saturday after American Civil Liberties Union officials won an emergency stay in federal court, meaning those affected with valid visas cannot be deported and sent back to their home countries. 

The order called for 120 days, no Syrians to be permitted to enter the United States, and for 90 days, residents of what the Trump Administration references as "terror-prone" countries of Iran, Iraq, Syria, Sudan, Libya, Yemen and Somalia also are banned, CNN reported.

In response to the immigration ban, Apple CEO Tim Cook told staff the company "wouldn't exist" without immigration, and that Apple managers do not support the policy reflected in the ban.

In an email to workers, obtained by Recode, Cook wrote:  "Apple would not exist without immigration, let alone thrive and innovate the way we do."

Cook also acknowledged that many Apple employees had voiced deep concerns about the executive order, reports Daily Mail. "I share your concerns. It is not a policy we support," he relayed. He then quoted Dr. Martin Luther King in the note to employees: "In the words of Dr. Martin Luther King, 'We may have all come on different ships, but we are in the same boat now.'"  

Facebook founder Mark Zuckerberg and Google CEO Sundar Pichai lead the outcries from business leaders. 

Zuckerberg wrote about Trump's restrictive immigration policies in a heartfelt Facebook post on Friday evening, citing vehement disagreement with Trump's promise to build a wall at the Mexican border, and his signing of an executive order to ban Syrian refugees and prevent immigrants from selected countries from entering the United States.

Zuckerberg, who is married to a first-generation immigrant, also wrote about his own European nationality and his hope that the nation can come together as one:  "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."

Pichai said the ban impacted nearly 200 of the company's employees, and urged them to return to the U.S. in a company-wide email, reports CNBC and The Wall Street Journal. He said he was upset about the affect of this order.

"We're concerned about the impact of this order and any proposals that could impose restrictions on Googlers and their families, or that could create barriers to bringing great talent to the US," a Google spokesperson told CNBC. "We'll continue to make our views on these issues known to leaders in Washington and elsewhere."

"Our first order of business is to help Googlers who are affected," Pichai said. "If you're abroad and need help, please reach out to our global security team." Pichai added that it was "painful to see the personal cost of this executive order on our colleagues."

Separately, Microsoft leaders also voiced concerns about the new ban. Both Microsoft CEO Satya Nadella and Google's Pichai are Indian-Americans.

Microsoft told CNBC in a statement that "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."

A federal judge granted an emergency stay Saturday to temporarily allow people with valid visas who landed in the U.S. to stay in the country. ACLU managers estimate it affected between 100 and 200 people detained at or in transit to U.S. airports. It did not, however, stay the president's entire order.

Canadian Prime Minister Justin Trudeau shared on social media Saturday a message for refugees rejected by Trump: "Canada will welcome you. To those fleeing persecution, terror & war, Canadians will welcome you, regardless of your faith. Diversity is our strength #WelcomeToCanada." 

Trudeau said he intends to talk to Trump about the success of Canada's refugee policy.