The United States Border Patrol has set up a checkpoint along the I-95 interstate highway in which agents can stop drivers and ask them to prove they are American citizens.

The Bangor Daily News reports that the checkpoint along I-95 "shut down the southbound lane between the Penobscot County towns of Howland and Lincoln" and created a roadblock that drivers could not avoid.

Although not everyone was stopped by the agents, those that were stopped were asked to prove they were American citizens, the Bangor Daily News claims.

"If you want to continue down the road, then we need to... what country you’re a citizen of," Border Patrol agents told one driver who passed through the checkpoint.

When asked what would happen to drivers if they refused to divulge their citizenship, the officers replied that drivers would only be allowed to go once "the agent is pretty sure that you’re U.S. citizens."

Emma Bond, the staff attorney of the ACLU of Maine, tells the Bangor Daily News that these checkpoints are a potential violation of drivers' constitutional rights.

"People have the right to be free from unreasonable searches and seizures, whether at a bus station or on the road," she says.

ICE agents have also been lurking around bus stations and asking bus riders to prove their citizenship before they're allowed to board.