WASHINGTON — The Pentagon has ordered about 1,500 active-duty soldiers to be ready in case of a possible deployment to Minnesota, where federal authorities have been conducting a massive immigration enforcement operation, two defense officials said Sunday.

The officials, who spoke on condition of anonymity to discuss sensitive military plans, said two infantry battalions of the Army’s 11th Airborne Division have been given prepare-to-deploy orders. The unit is based in Alaska and specializes in operating in arctic conditions.

One defense official said the troops are standing by to deploy to Minnesota should President Donald Trump invoke the Insurrection Act, a rarely-used 19th century law that would allow him to employ active duty troops as law enforcement.

The move comes just days after Trump threatened to do just that to quell protests against his administration’s immigration crackdown.

In an emailed statement, Pentagon chief spokesman Sean Parnell did not deny the orders were issued and said the military “is always prepared to execute the orders of the Commander-in-Chief if called upon.”

ABC News was the first to report the development.

On Thursday, Trump said in a social media post that he would invoke the 1807 law “if the corrupt politicians of Minnesota don’t obey the law and stop the professional agitators and insurrectionists from attacking the Patriots of I.C.E., who are only trying to do their job.”

Trump has repeatedly threatened to invoke the Insurrection Act throughout both of his terms. In 2020 he also threatened to use it to quell protests after George Floyd was killed by Minneapolis police, and in recent months he threatened to use it for immigration protests.

The law was most recently invoked by President George H.W. Bush in 1992 to end unrest in Los Angeles after the acquittal of four white police officers in the beating of Rodney King.