More than 2,000 "No Kings Day" protests were held on Saturday, organizers said.
Saturday marks the first full day of Marines on duty in Los Angeles, one week after protests against Immigration and Customs Enforcement raids ignited in LA and spread to other cities across the U.S., including New York City, San Francisco, Boston, and Austin, Texas.
Meanwhile, more than 2,000 "No Kings Day" protests were held across the U.S. on Saturday to protest the Trump administration and to counterprogram the military parade in Washington, D.C., organizers said. More than 5 million people participated, according to organizers.
The demonstrations remained peaceful in almost all cities, but as the evening grew in Los Angeles, tensions escalated between police and protesters.
The LAPD and other agencies are aggressively clearing the streets of downtown LA, where protestors had pushed up against police lines.
Crowds were pushed away from the federal building by police, some of whom were on horses.
Officers fired less lethal munitions and a type of gas.
-ABC News's Alex Stone
After a day of peaceful protests in Los Angeles, tensions mounted between protesters and Marines outside the federal building in downtown LA.
Some protesters chanted "shame" and booed the Marines, who were accompanied by federal law enforcement.
In Texas, the state capitol and capitol grounds were evacuated Saturday afternoon because of a "credible threat against state lawmakers planning to attend" the No Kings protest there, according to a Texas Department of Public Safety spokesperson.
An armed man who allegedly made threats against Republican officials has been detained while he was en route to Austin, a law enforcement official briefed on the situation told ABC News.
The Capitol grounds have since been reopened.
Thousands of "No Kings Day" protests were expected across the U.S. on Saturday to protest the Trump administration and to counterprogram the military parade in Washington, D.C.
Fliers reading "No Kings" were found in the car of the suspected gunman who is wanted for killing a Minnesota state lawmaker and wounding a second state lawmaker near Minneapolis early Saturday.
A 21-year-old man allegedly accelerated his SUV into a crowd of people at a "No Kings Day" rally in Virginia, hitting at least one person, according to Culpeper police.
No injuries were reported, police said.
Joseph Checklick Jr. was arrested for reckless driving and may face additional charges, police said.
-ABC News' Beatrice Peterson
