PORTLAND, Maine — The Maine American Civil Liberties Union is requesting information from federal officials on citizenship checks at local bus stations.

Zachary Heiden, legal director of the Maine ACLU, tells the Portland Press Herald a passenger notified the organization last week when U.S. Customs and Border Protection boarded their bus at the Bangor Transportation Center and asked riders about their citizenship.

No one was arrested. Still, Heiden says the ACLU filed a Freedom of Information Act request for records from the past year related to stops at the Bangor and Portland transportation centers.

The organization has yet to receive a response.

A U.S. Border Patrol representative confirmed there was an inspection in Bangor Jan. 14. He says the checks at transportation hubs are “vital” for national security.