The White House on Monday extended existing immigration restrictions through the end of December and expanded them to include foreign workers frequently hired by tech companies and other large U.S.-based employers. 

The announcement, codified in a presidential proclamation, suspends the entry of workers on H-1B specialty visas, which are most commonly used for employing foreign nationals in the tech sector, but also in academia and health care. 

The proclamation also bars people on H-4 visas for spouses of foreign workers, most types of H-2B nonagricultural work visas, most J-1 visas for exchange students and visitors, and L-1 visas that allow companies to transfer in foreign workers to U.S. outposts. 

The proclamation contains exceptions in the various categories and was not expected to affect people already in the United States on these visas, who are abroad and have the visa in hand, permanent residents, and certainly family members of U.S. residents.

The restrictions are the latest in a series of Trump administration efforts to curb legal immigration in the U.S., citing the coronavirus pandemic and the resulting economic crisis. 

[Trump announces temporary suspension of green cards]

Monday’s announcement follows a White House proclamation in April that suspended, for at least 60 days, the allocation of green cards to many immigrants abroad seeking to live and work in the United States on a permanent basis. That ban — now extended until December 31 — largely targeted family-based immigration, even though the president said at the time it was intended to help “put unemployed Americans first in line for jobs as America reopens.”

The president repeated his rationale on Monday.

"American workers compete against foreign nationals for jobs in every sector of our economy, including against millions of aliens who enter the United States to perform temporary work," he said in the proclamation.

"Temporary workers are often accompanied by their spouses and children, many of whom also compete against American workers," Trump continued. "Under ordinary circumstances, properly administered temporary worker programs can provide benefits to the economy.  But under the extraordinary circumstances of the economic contraction resulting from the COVID-19 outbreak, certain nonimmigrant visa programs authorizing such employment pose an unusual threat to the employment of American workers."

A senior administration official who spoke to reporters before the order was issued said the new restrictions will free up around 525,000 jobs. However, Alex Nowrasteh, director of immigration studies at the libertarian Cato Institute, asserted that reducing immigration at this time would actually “exacerbate COVID-19’s economic destruction and delay the eventual recovery.” 

“Shutting off this flow of skilled workers into the United States just when we need them the most will only harm hardworking people just trying to scrape by in the shadow of this devastating pandemic,” he said in a statement.

The Department of Homeland Security allocates 85,000 H-1B visas each year. The program has been highly criticized by lawmakers and organizations on both sides of the aisle for failing to protect U.S. workers and even exploiting foreign workers. It also has been vulnerable to misuse, critics say. 

But these visas also enjoy wide support in the business and tech sectors. Its proponents argue that H-1B workers fill positions that face a shortage of American workers. These visas are also often the only stepping stone to legal immigration for individuals who do not have direct family in the United States. 

“It is beyond misleading to imply that blocking foreign nationals creates jobs 1:1,” said Sarah Pierce, policy analyst at the nonpartisan Migration Policy Institute, in a tweet. She noted that 80 percent of the foreign nationals blocked in the April immigration proclamation are family-based, and that share may be higher once the families of the workers included in the expanded ban are factored in.

On the call with reporters, other senior administration officials added that the president had directed them to permanently reform the H-1B visa program so that it favors foreign workers who would make the highest annual U.S. salaries. 

In the past, Republican lawmakers have argued that there is little need for foreign labor in the country amid the coronavirus pandemic and called on the administration to suspend issuing guest worker visas for at least one year as more businesses begin to reopen.

“As we respond to the COVID-19 outbreak, it is important that we continue to look out for their economic welfare. More than 36 million Americans have filed for unemployment and, even as states and counties begin to reopen, jobs are scarce,” Rep. Andy Biggs of Arizona and other lawmakers said in letter to Trump last month. 

However, the announcement contradicts efforts the administration has made in the past weeks to help U.S. employers hire employees using specialty visas. In May, for example, the Trump administration issued a regulation to make it easier for some seasonal workers on H-2B visas who are "essential to the U.S food supply chain" to remain in the country by temporarily amending visa requirements.

Foreign workers on H-2B visas who are already in the U.S. will be allowed to stay longer without first returning to their home countries and can start right away without waiting for full approval, according to the regulation published in the Federal Register.