July 8 (UPI) -- Los Angeles Mayor Karen Bass has criticized the federal government as "un-American" over its deployment of U.S. troops to MacArthur Park as part of President Donald Trump's crackdown on immigration. U.S. troops and armed federal immigration agents were seen Monday, including military vehicles, descending upon MacArthur Park. Bass posted footage of the operation, showing heavily armed law enforcement and mounted personnel walking in formation across a soccer field. The Department of Defense said in a statement that the soldiers were on the ground "to ensure the safety of federal agents." "We will protect federal law enforcement and assist by establishing a security perimeter." The results and nature of the operation were unknown. Bass lambasted the Trump administration during a press conference later Monday for deploying troops to the park, which she said displaced children attending a summer camp there. She said the operation was part of Trump's "political agenda of provoking fear and terror." "Frankly, it is outrageous and un-American that we have federal armed vehicles in our parks when nothing is going on in the parks. It's outrageous and un-American that the federal government seized our state's National Guard. It's outrageous and un-American that we have U.S. Marines who are trained to kill foreign soldiers overseas deployed in our American city. Trump seized and then deployed some 2,000 California National Guardsmen to Los Angeles in response to protests erupting June 6 in response to Immigration and Customs Enforcement raids. Since then, more than 4,000 Guardsmen and hundreds of U.S. Marines have been deployed in the city to aid federal immigration operations. The New York real estate mogul returned to the White House in January after employing often derogatory rhetoric and misinformation about migrants during his campaign in support of his plans to conduct mass deportations. Amid his second term, Trump has tried to make good on his campaign promises, but has attracted criticism for attacking the due process rights of migrants as well as facing litigation. Bass chastised Trump's immigration policy of deploying U.S. troops in American cities for trying to instill fear and stoke chaos. "Home Depot one day, a car was the next, armed vehicles and what looked like mounted military units in a park the next day," she said. "What happened to the criminals, the drug dealers, the violent individuals? Who were in the park today were children. It was their summer camp." During a press conference Monday on the six-month anniversary marking the Los Angeles fires, California Gov. Gavin Newsom described what had happened at MacArthur Park earlier in the day as a "disgrace" and "theater." "That's the message from the polluted heart of the president of the United States. That's the message of the polluted heart of Stephen Miller," he said, referring to Trump's White House deputy chief of staff for policy and homeland security advisor. "Those National Guards men and women that were out there protecting people are not being used as political pawns, out there on horseback, running through soccer fields in the middle of the day, timed around announcements and events like this, saying everything you and I need to know about the state of mind of the president of the United States and this administration."