U.S. immigration “preclearance” facilities at foreign airports might be breaking those countries’ antidiscrimination laws.

As part of our multiple tactics to keep up the pressure against President Trump’s Muslim immigration ban, on Friday the ACLU filed a Freedom of Information Act request with U.S. Customs and Border Protection demanding records on the implementation of the executive order at all 15 CBP “preclearance” airport locations abroad. These are facilities at airports in other countries where people coming to the U.S. go through U.S. immigration and customs before being allowed to get on their flights.

The preclearance program operates in Canada, Ireland, Aruba, the Bahamas, Bermuda, and the United Arab Emirates (although CBP plans to expand to other countries). The potential impact of the policies at these locations is significant, as some 16 million people heading to the U.S. went through preclearance in 2015.

Our FOIA request also asks for documents relating to compliance with court rulings stopping the order from being carried out. Before those court decisions, news reports documented several instances already of people traveling to the U.S. being prevented entry to the United States and having their visas revoked because they were citizens of one of the seven banned majority-Muslim countries. A Syrian doctor, for example, was refused admission at preclearance in the Abu Dhabi airport, where his valid visa was also cancelled. The stories also report on one person who was turned away in Ireland and five Canadians of Moroccan origin denied entry.

Both Ireland and Canada have expressed serious concerns over the executive order and its implementation at airports on their soil. The Irish prime minister ordered a complete review of the preclearance program in Ireland, and Irish and U.S. officials are meeting to discuss the executive order this month.

Canada, which hosts 9 of the 15 preclearance locations at airports, has ordered an investigation as to whether the implementation of the executive order violates Canadian law. A spokesperson for the Canadian government warned, “Any U.S. pre-clearance activities in Canada have to be carried out in a manner consistent with Canadian law, including the Canadian Charter of Rights and Freedoms, the Canadian Bill of Rights and the Canadian Human Rights Act.”

Today, President Trump is meeting for the first time with Canadian Prime Minister Justin Trudeau. They are likely to discuss the executive order, which not only affects Canada as a major host for the preclearance program, but also Canadian citizens, many of whom frequently travel to the U.S. — and many of whom are Muslim.

Some Canadian Muslims have already been subject to intense questioning at the border about their religious observance and opinions on Trump since the executive order went into effect. Even if the president issues a narrower version of the travel and refugee ban, this improper treatment of Muslim travelers by CBP officers could continue.

The Canadian Civil Liberties Association voiced support for our FOIA request, calling it “an important accountability measure and check on government powers.” Sukanya Pillay, the CCLA’s executive director and general counsel, added, “Transparency and a clear understanding of rules is a bulwark against unlawful discrimination and overreach.” 

Canada is right to make sure the Muslim ban does not violate domestic and international law banning religious profiling and discrimination. Attention and pressure from the countries who host preclearance facilities may play an important role in reminding Trump of the growing costs of his executive order.