The American Civil Liberties Union is demanding that customs agents turn over documents showing whether anyone has been detained or turned away from Minneapolis-St. Paul International Airport due to President Donald Trump’s executive order banning refugees and travelers from a list of predominantly Muslim countries.

Minnesota’s ACLU, in coordination with a dozen neighboring chapters, filed suit this week demanding the Chicago field office for U.S. Customs and Border Protection release the records.

A spokeswoman for the ACLU said the group filed a legal request for the documents earlier this year, but the agency has “failed to substantively respond,” which prompted the suit.

“The government is bound by law to release information about the treatment of people at the borders and we are very disappointed that we have to file a lawsuit in order to get access to it,” said John Gordon, ACLU-MN’s interim legal director, in a statement. “Transparency of government action is important to ensure that everyone’s rights are respected.”

In January, Trump signed an executive order temporarily blocking citizens from several predominantly Muslim nations, including refugees. After a judge blocked the order, questioning its constitutionality, Trump signed a revised order in March. Hawaii quickly filed suit, and a judge there has blocked the new version.