WATCH: Border Patrol and ICE leaders defend tactics used in Minneapolis operations

Top immigration officials touted the arrests they have made in Minnesota and defended the tactics used by Border Patrol and Immigration and Customs Enforcement during a press conference in Minneapolis Tuesday.

Watch the press briefing in the video player above.

"Over the course of this administration, more than 10,000 criminal illegal aliens, as I said, have been apprehended here in Minneapolis over the past year. And in just the last six weeks, the last six weeks alone, during this most current surge, 3,000 arrests of some of the most dangerous offenders operating in Minneapolis have occurred," said Border Patrol senior official Greg Bovino.

READ MORE: A U.S. citizen says ICE forced open the door to his Minnesota home and removed him in his underwear after a warrantless search

ICE and Border Patrol officers have used aggressive tactics during the recent crackdown, including breaking down the door of a family's home without a judicial warrant and pulling people from vehicles.

Immigration officers' tactics are "born of necessity," Bovino said, and "well-grounded in law."

"Everything we do is legal, ethical and moral," he said.

Julia Decker, policy director at the Immigrant Law Center of Minnesota, expressed frustration that advocates have no way of knowing whether the government's arrest numbers and descriptions of the people in custody are accurate.

Meanwhile, federal prosecutors served grand jury subpoenas Tuesday to Minnesota officials as part of an investigation into whether they obstructed or impeded law enforcement during a sweeping immigration operation in the Minneapolis-St. Paul area, a person familiar with the matter said.

The subpoenas, which seek records, were sent to the offices of Gov. Tim Walz, Attorney General Keith Ellison, Minneapolis Mayor Jacob Frey, St. Paul Mayor Kaohly Her and officials in Ramsey and Hennepin counties, the person said.

The person was not authorized to publicly discuss an ongoing investigation and spoke to The Associated Press on condition of anonymity.

The subpoenas are related to an investigation into whether Minnesota officials obstructed federal immigration enforcement through public statements they made, two people familiar with the matter said Friday. They said then that it was focused on the potential violation of a conspiracy statute.

Walz and Frey, both Democrats, have called the probe a bullying tactic meant to quell political opposition. Frey's office released a subpoena, which requires a long list of documents for a grand jury on Feb. 3, including "any records tending to show a refusal to come to the aid of immigration officials."

The Justice Department called the state's lawsuit, filed soon after the fatal shooting of Renee Good by an immigration officer, "legally frivolous."

Good, 37, was killed on Jan. 7 as she was moving her vehicle, which had been blocking a Minneapolis street where ICE officers were operating. Trump administration officials say the officer, Jonathan Ross, shot her in self-defense, although videos of the encounter show the Honda Pilot slowly turning away from him.

Since then, the public has repeatedly confronted officers, blowing whistles and yelling insults at ICE and Border Patrol. They, in turn, have used tear gas and chemical irritants against protesters. Bystanders have recorded video of officers using a battering ram to get into a house as well as smashing vehicle windows and dragging people out of cars.