A United States federal judge on Saturday blocked part of the controversial ban on travelers from seven Muslim-majority countries imposed by the U.S. President.

Judge Ann M. Donnelly of the Federal District Court in Brooklyn ruled that refugees or other people affected by the measure and who have arrived at U.S. airports cannot be deported to their countries.

In an emergency hearing, the judge ruled on a petition filed by the American Civil Liberties Union (ACLU) against the executive order signed by Donald Trump on Friday, a week after being sworn in as president.

The ACLU, a nationwide civil rights organization, filed the suit after two Iraqi citizens with valid visas to enter the U.S. were detained at the John F. Kennedy airport in New York.

According to the ACLU, between 100 and 200 people have been detained upon arrival at U.S. airports since Trump signed the order, although the government is yet to confirm the figures.

The judge concluded that implementing the order and sending the travelers back to their home countries could cause them “irreparable harm,” according to local media reports.

However, Donnelly did not rule on whether the affected people can be allowed to stay in the country, or the constitutionality of the measure, and set a hearing on the matter for Feb. 21.

On Friday, Trump signed a controversial executive order to fight against terrorism.

The order calls for the suspension of all refugee arrivals for a period of 120 days in order to examine the vetting mechanisms and make sure no terrorists are accepted on American soil.

It also suspends for 90 days the issuing of visas to all citizens of seven predominantly Islamic countries until a process of extreme vetting is adopted. EFE