The department said in a press release that it kicked off “Operation Catch of the Day” on Tuesday, targeting those it called criminal offenders.

More than 100 agents arrived in the frigid northeast state this week, one current immigration official and one former official said on condition of anonymity.

The former official said the operation would focus on refugees.

Maine’s political leadership and immigrant communities have been bracing for the arrival of more immigration agents.

Maine Governor Janet Mills, a Democrat, said last week that the Trump administration’s aggressive enforcement tactics were “not welcome.”

Trump, a Republican, has surged immigration agents to Democratic-led cities and states since mid-2025, with some 3,000 federal agents deployed to Minnesota in recent weeks.

Trump has called the intense enforcement operations necessary to combat criminality, although many suspected immigration offenders arrested have no criminal charges or convictions.

Trump has been critical of Somali immigrants after some Somali Americans were implicated in a fraud scheme in Minnesota, calling them “garbage” and saying they should leave the US.

“If the federal government has warrants, then it should show them,” Mills said in a statement on Wednesday, in which she added that many people in her state were “fearful.”

Mills, in her second term as Maine’s governor, is running for a US Senate seat currently held by Republican Susan Collins, a moderate trying to fend off Democratic challengers in November’s midterm elections that will decide control of Congress.

Trump’s immigration policies are expected to be a prominent issue in Maine and other states.

Public support for Trump’s approach to immigration has dwindled in recent months as federal agents have swept through residential neighbourhoods, tossing tear gas and clashing with protesters, Reuters/Ipsos polls show.

Tensions boiled over this month when a US Immigration and Customs Enforcement officer in Minneapolis fatally shot Renee Good, US citizen and mother of three.

Carl Sheline, mayor of Lewiston, Maine, said on Tuesday that the city had seen an increase in ICE agents in the 39,000-person city.

Lewiston, the second-largest city in Maine, is home to Somali immigrants and other refugees, communities that have been there for decades.

Sheline said in an email that ICE’s “terror and intimidation tactics” showed “a complete lack of humanity.”

“Lewiston stands for the dignity of all the people who call Maine home,” he said.

DHS spokesperson Tricia McLaughlin criticised Maine’s governor, calling her one of the state’s “sanctuary politicians” trying to limit cooperation with federal immigration enforcement.

“We are no longer allowing criminal illegal aliens to terrorise American citizens,” McLaughlin said in a statement.