NEW YORK (AP) – Google, Apple and other tech giants are expressing dismay over an executive order on immigration from President Donald Trump that bars nationals of seven Muslim-majority countries from entering the U.S.

The U.S tech industry relies on foreign engineers and other technical experts for a sizeable percentage of its workforce. The order bars entry to the U.S. for anyone from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen for 90 days.

The move, ostensibly intended to prevent extremists from carrying out attacks in the U.S., could now also heighten tensions between the new Trump administration and one of the nation’s most economically and culturally important industries. That’s especially true if Trump goes on to revamp the industry’s temporary worker permits known as H-1B visas, as some fear.

Apple CEO Tim Cook wrote in a memo to employees that “We have reached out to the White House to explain the negative effect on our coworkers and our company.”