WATCH LIVE: Defense officials testify on National Guard deployment across U.S. in Senate hearing

WASHINGTON (AP) — Senators for the first time are poised to question military leaders over President Donald Trump’s use of the National Guard in American cities, an extraordinary move that has prompted legal challenges as well as questions about states’ rights and the use of the military on U.S. soil.

The Senate Armed Services Committee hearing is expected to begin at 9:30 a.m. EST. Watch live in our video player above.

The hearing Thursday before the Senate Armed Services Committee is expected to feature tough questioning for Pentagon leaders over the legality of the deployments, which in some places were done over the objections of mayors and governors.

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The hearing will bring the highest level of scrutiny to Trump’s use of the National Guard outside of a courtroom since the deployments began and comes a day after the president faced another legal setback over his muscular use of troops in larger federal operations.

Trump has justified the use of the military in American cities by saying the National Guard is needed to support federal law enforcement, protect federal facilities and combat crime.

Democratic Sen. Tammy Duckworth, D-Ill., said she had threatened to hold up the annual defense bill if Republican leadership continued to block the hearing, which she said is long overdue.

“Donald Trump is illegally deploying our nation’s service members under misleading if not false pretexts,” Duckworth told The Associated Press.

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Duckworth, a combat veteran who served in the Illinois National Guard, said domestic deployments have traditionally involved responding to major floods and tornadoes, not assisting immigration agents who are detaining people in aggressive raids.

Duckworth said she has questions for the military about how Trump’s deployments are affecting readiness, training and costs. She also wants to know if Guard members will have legal protections if an immigration agent wrongfully harms a civilian.

“I’m deeply concerned that our nation’s military is being put in jeopardy by these policies,” Duckworth said.

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The hearing comes two weeks after two West Virginia National Guard members deployed to Washington were shot just blocks from the White House in what the city’s mayor described as a targeted attack. Spc. Sarah Beckstrom died a day after the Nov. 26 shooting, and her funeral took place Tuesday. Staff Sgt. Andrew Wolfe is still hospitalized in Washington.

Meanwhile, a federal judge in California on Wednesday ruled that the Trump administration must stop deploying the California National Guard in Los Angeles and return control of the troops to the state.

U.S. District Judge Charles Breyer in San Francisco granted a preliminary injunction sought by California officials, but also put the decision on hold until Monday. The White House said it plans to appeal.

Trump called up more than 4,000 California National Guard troops in June without Gov. Gavin Newsom’s approval to further the Trump administration’s immigration enforcement efforts.

The move was the first time in decades that a state’s National Guard was activated without a request from its governor and marked a significant escalation in the administration’s efforts to carry out its mass deportation policy. The troops were stationed outside a federal detention center in downtown Los Angeles where protesters gathered and later sent on the streets to protect immigration officers as they made arrests.

The number had dropped to several hundred by late October. The 100 or so California troops that remain in Los Angeles are guarding federal buildings or staying at a nearby base and are not on the streets with immigration enforcement officers, according to U.S. Northern Command.

Trump also had announced National Guard members would be sent to Washington, D.C., Illinois, Oregon, Louisiana and Tennessee. Other judges have blocked or limited the deployment of troops to Portland, Oregon, and Chicago, while Guard members have not yet been sent to New Orleans.