Sen. Elizabeth Warren (D-Mass.) has asked President Trump’s top Cabinet officials to pledge that they will not deploy federal agents to U.S. cities to quell protests, specifically in the event that Trump loses reelection and refuses to leave the office.

“I therefore write to seek your assurances that you will not allow the military or civilian forces under your control to be used by the President to suppress dissent and democracy,” Warren wrote Tuesday in a letter to Defense Secretary Mark Esper, Attorney General William Barr, Interior Secretary David Bernhardt and acting Homeland Security Secretary Chad Wolf.

President Trump said in an interview with Fox News Sunday that he’ll “have to see” about accepting the results of the election.

“The potential for President Trump to activate domestic forces as his ‘personal militia’ (as former Secretary of Homeland Security Tom Ridge put it) is even more disturbing given his ongoing refusal ‘to reassure the country that he would abide by the voters’ will’ and peacefully leave office if he is voted out – resulting in ‘an unprecedented test of American democracy,’ ” Warren wrote, quoting a Washington Post article.

Warren noted that Trump has threatened to send federal troops to more American cities after doing so in Portland, Seattle and Chicago, "despite clear opposition from governors, mayors, and citizens who are exercising their First Amendment rights in the communities in which these federal personnel have been deployed."

"I urge you not to allow these personnel under your command or supervision to be used in any future domestic actions against people exercising their right to protest," Warren wrote.

Warren’s letter came the same day that Barr testified before the House Judiciary Committee, defending the deployment of federal troops to U.S. cities, saying he had issued the orders to protect federal buildings "under attack" and combat violent crime.

When asked if he would accept the election results, Barr said: “Well, if the results are clear, I would leave office.”