President Trump Monday signed an executive order temporarily suspending many nonimmigrant visas, including temporary H-1B visas popular among tech companies. Industry executives say the move will push highly skilled tech workers and prospective innovators to other countries.

The executive order also suspends for the rest of the year most J-1 visas, designed for research scholars and professors participating in cultural exchange programs; H-2B visas for seasonal nonagricultural workers; and L-1 visas, which companies use to transfer existing employees to offices in the US. The order will not affect workers who are already in the country.

The administration says that, while the US continues to suffer from the economic fallout of the Covid-19 pandemic, nonimmigrant visa programs “pose an unusual threat to the employment of American workers.” The administration said the move will give US workers access to an additional 525,000 jobs, including the 170,000 vacated by an April ban on green-card holders coming to the US.

But researchers say there’s little evidence that barring new visas will help the US economy recover from the pandemic. Sectors with lots of H-1B visas are more likely to have low US unemployment rates, according to a recent report from the immigration- and trade-focused research group the National Foundation for American Policy, which examined US visa figures from 2008 to 2018.

Tech companies have for years relied on the H-1B visa program to bring software engineers and others into the country from countries including India, China, Canada, and South Korea. Tech firms are among the biggest—and most successful—users of the competitive program. The Trump administration has been rejecting a greater share of H-1B applications since it took office. Yet in fiscal 2018, US Citizenship and Immigration Services says 99 percent of the 4,519 applicants sponsored by Microsoft were granted H-1B visas; 98 percent of Amazon’s 5,480 were, too. Apple, Intel, Google, and Facebook are also among the top users of the program.

Tech leaders and their allies condemned the executive order. “Immigration has contributed immensely to America’s economic success, making it a global leader in tech, and also Google the company it is today,” Alphabet CEO Sundar Pichai, himself an immigrant from India, wrote on Twitter. “Disappointed by today’s proclamation—we’ll continue to stand with immigrants and work to expand opportunity for all.”

Box CEO Aaron Levie called the order “unbelievably bad policy on every level. It will only mean more jobs move outside the US, and in no way makes America better or more competitive.”