AUGUSTA — Maine’s top prosecutor has urged the head of Homeland Security to stop arresting immigrants in and around Maine courthouses.

Attorney General Janet Mills warned that “the recent action of ICE agents at the Cumberland County Courthouse will have an unnecessary chilling effect on our efforts to obtain the cooperation of victims and our successful prosecution of crimes,” according to a Monday letter addressed to John F. Kelly, secretary of Homeland Security, and Richard W. Murphy, acting U.S. attorney.

Mills released the letter a few hours after a similar statement signed by 179 Maine lawyers was sent out to media by the American Civil Liberties Union.

Both were sparked by last week’s arrest of Abdi Ali, 28, of Portland by Immigration and Customs Enforcement agents at the Cumberland County Courthouse.

“In investigating matters of human trafficking, domestic violence and the like, it is critical to us that all individuals have free and open access to Maine courts, regardless of their immigration status,” Mills said in her letter.

Chief Justice Leigh Saufley, who oversees administration of the courts, declined through a spokeswoman to comment on the letters.

“The chief justice is carefully looking at these issues and how they are being handled in other states,” said Mary Ann Lynch, spokeswoman for the courts.

ICE has used similar tactics elsewhere, including in New England.

In Vermont, members of that state’s Congressional delegation expressed concern last month over ICE’s tactics after three farm workers advocates were arrested, according to the Burlington Free Press. One was taken into custody at a Burlington courthouse.

In March, ICE agents arrested five people who were at the Lawrence, Massachusetts, office of US Citizenship and Immigration Services for scheduled appointments, the The Boston Globe reported. Three of those people were seeking green cards, according to public radio station WBUR.

In California, the chief justice of the state supreme court criticized ICE agents for using courthouses as “bait,” according to the Washington Post.

Maine Attorney General Janet Mills