Warren calls on agency chiefs to commit to not deploying federal forces on Americans should Trump not leave office

"You are each responsible for the command of military or civilian troops and domestic law," the Massachusetts Democrat wrote in a letter Tuesday to Defense Secretary Mark Esper, Attorney General Bill Barr, Interior Secretary David Bernhardt and acting Homeland Security Secretary Chad Wolf.

Warren pointed to Trump's threats to send federal authorities to more US cities -- after deploying forces 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."

And she raised concerns over whether Trump will use federal forces against civilians should he lose reelection and deny a peaceful transition of power -- a scenario Democrats have raised and Trump has stoked by refusing to say he will accept the election results.

She requested the secretaries' commitments, as well as information on any federal requests to activate their agencies' forces by August 3.

"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 also expressed concern over "the potential for President Trump to activate domestic forces as his 'personal militia' (as former Secretary of Homeland Security Tom Ridge put it)," "given his ongoing refusal" to say he will accept the presidential election results and peacefully leave 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," she added.

In an interview earlier this month, Trump repeatedly refused to affirm that he would accept the results of the election in November, claiming falsely that mail-in ballots could rig the outcome."I have to see. No, I'm not going to just say yes," Trump said when pressed on "Fox News Sunday" about whether he would accept the results. "I'm not going to say no, and I didn't last time either."

Prior to Warren's letter, Barr addressed such issues during his testimony Tuesday before the House Judiciary Committee, where he said that federal officers had been sent to protect federal buildings "under attack" and combat violence crime in cities. Barr said that he has made clear to the Trump administration that he "would like to pick the cities" where federal law enforcement officers are deployed under a Justice Department crime-fighting program "based on law enforcement need."

Asked what he would do if Trump lost the election but refused to leave office, Barr caveated his answer: "If the results are clear, I would leave office."