Protests live updates: Marines make 1st temporary detention in LA

The Federal Bureau of Investigation is seeking information about a man in Paramount, California, who allegedly threw rocks at police and law enforcement vehicles during the protest on Saturday.

The FBI is offering a reward of up to $50,000 for information about the suspect.

The incident happened at approximately 3:30 p.m. on Saturday, according to the FBI, when the suspect threw rocks at law enforcement vehicles on Alondra Boulevard in Paramount, injuring a federal officer and damaging government vehicles.

FBI Deputy Director Dan Bongino said in a statement that officials will use tools to investigate "those who chose violence" in Los Angeles.

"We will be investigating and pursuing all available leads for assault on a federal officer, in addition to the many arrests already made," Bongino said.

-ABC News' Luke Barr

The Los Angeles Police Department has declared unlawful assembly in the Alameda area of Los Angeles between Temple and Aliso streets.

"All persons must leave the area or be subject to arrest," police said.

Additionally, the use of less lethal munitions has been authorized.

"Persons throwing items at officers will be detained and arrested," police added.

-ABC News' Tristan Maglunog and Alyssa Starr

The Los Angeles Police Department is going on "Tactical Alert" on Sunday -- just as the police force did for several hours on Friday -- amid ongoing immigration protests.

The term signifies a heightened level of response and preparedness where officers can be kept on past their shift end time and moved around between divisions.

This type of response is often deployed when major events occur in the city, which require significant resources.

-ABC News' Alex Stone

President Donald Trump posted on Truth Social on Sunday, instructing his administration -- specifically Secretary of Homeland Security Kristi Noem, Secretary of Defense Pete Hegseth and Attorney General Pam Bondi -- to take all necessary actions to "liberate Los Angeles from the migrant invasion."

Trump claimed that "violent insurrectionist mobs" are attacking federal agents to halt his administration's deportation efforts.

"Order will be restored, the Illegals will be expelled, and Los Angeles will be set free," Trump wrote.

On Saturday, Trump signed a memorandum to deploy the National Guard as protests in Los Angeles entered their third consecutive day. The memorandum stated that up to 2,000 service members could be deployed for a duration of 60 days or as determined by the defense secretary. The National Guard arrived in Los Angeles overnight.

Both the president and the secretary of defense have not ruled out sending Marines to California.

-ABC News' Kelsey Walsh