Changes to the U.S. visa waiver program, which has undergone increased scrutiny in the aftermath of the terrorist attacks in Paris and San Bernardino, California, could violate the recent nuclear agreement with Iran, Iran’s deputy foreign minister warned. Under the rules, foreign visitors who have traveled to certain countries in the Middle East must now apply for visas if they want to get into the United States.

The visa waiver program allows citizens of 38 countries to enter the U.S. easily without first obtaining a visa. The program is designed to ease business travel and tourism. The Iranian official said the new restrictions on individuals who have been to Syria, Iraq, Iran and Sudan in the past five years would adversely affect trade and tourism, violating the Iranian nuclear agreement, the Associated Press reported.

The nuclear agreement, which sought to ensure the Persian country does not enrich uranium to a level that could be used to make a nuclear weapon, also intended to normalize relations between Iran and the West.

The waiver program came under scrutiny especially after the Paris attacks, as it was discovered that some of the attackers may have traveled freely to Syria and back on European passports. While refugee screening is fairly extensive for individuals hoping to find safe haven in the United States after enduring hardship in civil-war-fraught countries like Syria, allowing individuals with Western passports to freely cross U.S. borders after visiting those countries has been seen as a potential safety risk. The refugee process has also come under attack by lawmakers, including top Republican presidential candidates.

U.S. President Barack Obama has been criticized widely by opponents for the Iranian nuclear agreement, which they allege is too generous to Iran and lifts sanctions without actually ensuring that the country is unable to develop a nuclear arsenal.