U.S. President Donald Trump speaks before signing an executive order directing federal agencies to recommend changes to a temporary visa program used to bring foreign workers to the United States to fill high-skilled jobs during a visit to the world headquarters of Snap-On Inc, a tool manufacturer, in Kenosha, Wisconsin, U.S., April 18, 2017. REUTERS/Kevin Lamarque

(Reuters) - A group of chief executive officers at the largest U.S. companies expressed serious concern about the Trump administration’s immigration policy and said the rules increase uncertainty and undermine economic growth.

In the letter signed by 59 CEOs including Tim Cook of Apple Inc AAPL.O, JPMorgan Chase & Co's JPM.N Jamie Dimon and Doug Parker of American Airlines AAL.O, the executives said that many of their employees were now facing uncertainty due to issues such as 'inconsistent immigration decisions' that would likely curtail work permits for spouses of skilled immigrants.

“As the federal government undertakes its legitimate review of immigration rules, it must avoid making changes that disrupt the lives of thousands of law-abiding and skilled employees, and that inflict substantial harm on U.S. competitiveness,” the CEOs said in a letter dated Wednesday.

The CEOs are a part of the Business Roundtable, which is a lobbying group and is currently chaired by Dimon. While Business Roundtable has been discussing immigration policy for years, the letter was prompted by specific recent regulatory actions taken by U.S. Citizenship and Immigration Services, which is soon expected to revoke work authorization eligibility for spouses.

“Together, the USCIS actions significantly increase the likelihood that a long-term employee-who has followed the rules and who has been authorized by the U.S. government multiple times to work in the United States-will lose his or her status,” the letter said.

“At a time when the number of job vacancies are reaching historic highs due to labor shortages, now is not the time restrict access to talent,” the letter added.

The government should not change the rules in the middle of the process as it could result in unnecessary costs and complications, the executives said in a letter to the Homeland Security Secretary Kirstjen Nielsen.

Nielsen, a Trump appointee, told reporters at a White House briefing on Thursday that the administration was only strictly enforcing the law.

“This administration did not create a policy of separating families ... What has changed is that we no longer exempt entire classes of people who break the law,” she said.