Silicon Valley is stepping up its confrontation with the Trump administration.

On Sunday night, technology giants Apple, Facebook, Google, Microsoft, Netflix, Twitter, Uber and many others filed a legal brief opposing the administration’s contentious entry ban, according to people familiar with the matter. The move represents a rare coordinated action across a broad swath of the industry – 97 companies in total – and demonstrates the depth of animosity toward the Trump ban.

The amicus brief was filed with the U.S. Court of Appeals for the 9th Circuit, which is expected to rule within a few days on an appeal by the administration after a federal judge in Seattle late Friday issued a temporary restraining order putting the entry ban on hold. The brief comes after a week of nationwide protests against the plan – as well as a flurry of activity in Silicon Valley, a region that sees immigration as central to its identity as an innovation hub.

After a federal judge in Seattle temporarily blocked enforcement of President Trump’s travel ban, government authorities immediately told airlines to allow travel by those who had been barred, a U.S. official said.

Companies backing the filing also include Lyft, Pinterest, Yelp, Square, Reddit, Kickstarter, Github, Glassdoor, Box, Mozilla, Dropbox, Twilio, Zynga, Medium, Pinterest and Salesforce, according to the sources, who spoke on condition of anonymity.

Notably, it doesn’t appear that Amazon is party to the brief. Amazon’s founder, Jeffrey P. Bezos, who also owns The Washington Post, recently said that he supported the lawsuit filed by Washington state’s attorney general against the executive order on immigration and refugees.

On Monday, an Amazon spokesperson said the state’s attorney general preferred that the company not join the amicus since they are a witness in the original lawsuit.

The filing says that the entry ban, which barred individuals from seven majority-Muslim countries from entering the U.S. for at least 90 days and suspended the U.S. refugee program, is discriminatory.

“The order represents a significant departure from the principles of fairness and predictability that have governed the immigration system of the United States for more than 50 years,” the brief said. “The order makes it more difficult and expensive for U.S. companies to recruit, hire, and retain some of the world’s best employees. It disrupts ongoing business operations. And it threatens companies’ ability to attract talent, business, and investment to the United States.”

The legal briefing argues that immigration and economic growth are “intimately tied” and that the order would damage the U.S.’s ability to attract the world’s talent.

“Immigrants or their children founded more than 200 of the companies on the Fortune 500 list, including Apple, Kraft, Ford, General Electric, AT&T, Google, McDonald’s, Boeing, and Disney,” it said. The briefing also notes prominent immigrant and refugee writers, scholars and Nobel laureates.

“Long-term, this instability (caused by the executive order) will make it far more difficult and expensive for U.S. companies to hire the world’s best talent – and impede them from competing in the global marketplace,” it says.

“The problems that render the executive order harmful to businesses and their employees also make it unlawful,” the brief said.

An estimated 37 percent of the workforce in Silicon Valley is foreign-born, according to the think tank Joint Venture.