The Pentagon will send a Marine battalion to Los Angeles in a major escalation of US President Donald Trump’s response to anti-immigration enforcement protests, the United States military has said.

The statement on Monday confirmed the “activation” of 700 Marines to help protect federal personnel and property in the California city, where Trump had deployed the US National Guard a day earlier.

The update came despite opposition from state officials, including California’s Governor Gavin Newsom, who had earlier mounted a legal challenge to the deployment of the National Guard troops.

In a statement, the military said the “activation of the Marines” was meant to help “provide continuous coverage of the area in support of the lead federal agency”.

Speaking to the Reuters news agency, an unnamed Trump administration official said the soldiers would be acting only in support of the National Guard and other law enforcement.

The official said that Trump was not yet invoking the Insurrection Act of 1807, which would suspend legal limitations that block the military from taking part in domestic law enforcement.

Speaking shortly before the reports emerged, Trump said he was open to deploying Marines to Los Angeles, but said protests in the city were “heading in the right direction”.

“We’ll see what happens,” he said.

Reporting from Los Angeles, Al Jazeera’s Rob Reynolds said protests on Monday organised in the city centre by union groups were peaceful.

He noted that the National Guard which Trump had deployed to the city on Sunday played a minimal role in responding to the protests, only guarding federal buildings. That raised questions over why the Trump administration would feel a Marine deployment was needed.

“[The National Guard] didn’t engage with the protesters. They didn’t do much of anything other than stand there in their military uniforms,” Reynolds said.

He added that there is an important distinction between the National Guard, a state-based military force usually composed of part-time reserves, and the more combat-forward Marines, which are the land force of the US Navy.

“Now the Marines, this is a whole different thing. The United States sends Marines overseas where US imperialist interests are at stake, but not to cities in the United States,” he said.

California Governor Newsom’s office, meanwhile, said that according to the information it had received, the Marines were only being transferred to a base closer to Los Angeles, and not technically being deployed onto the streets.

Still, it said the “level of escalation is completely unwarranted, uncalled for, and unprecedented – mobilising the best in class branch of the US military against its own citizens”.

California mounts challenge

The updates on Monday came shortly after Newsom and California Attorney General Rob Bonta announced the state had filed a lawsuit challenging Trump’s decision to deploy the National Guard to Los Angeles.

Newsom has maintained that local law enforcement had the capacity to respond to protests over US Immigration and Customs Enforcement (ICE) raids in Los Angeles and the nearby city of Paramount that first broke out on Friday.

The Democratic state leader accused Trump of escalating the situation, saying in a statement that the president was “creating fear and terror by failing to adhere to the US Constitution and overstepping his authority”.

“This is a manufactured crisis to allow him to take over a state militia, damaging the very foundation of our republic,” Newsom said.

The California lawsuit argues that the legal authority Trump invoked to deploy the National Guard requires the consent of the state’s governor, which Newsom did not provide.

For his part, Trump indicated he would support Newsom being arrested for impeding immigration enforcement, responding to an earlier threat from the president’s border czar, Tom Homan.

Trump’s response to the protests represented the first time since 1965 that a president deployed the National Guard against the will of a state governor. At the time, President Lyndon B Johnson did so to protect civil rights demonstrators in Alabama.

Protests continue

Protests against Trump’s crackdown – as well as his overall immigration policy – continued on Monday.

Standing in front of Ambiance Apparel in Los Angeles, one of the sites raided by ICE agents last week, Indigenous community leader Perla Rios spoke alongside family members of individuals detained by immigration agents.

Rios called for due process and legal representation for those taken into detention.

“What our families are experiencing is simply a nightmare,” Rios said.

Meanwhile, the Service Employees International Union (SEIU) called for protests in cities across the country over the Trump administration’s response to demonstrations, which included the arrest of the union’s California president David Huerta.

Huerta was detained on Friday during immigration raids and charged with conspiracy to impede an officer during immigration enforcement operations.

“From Massachusetts to California, we call for his immediate release and for an end to ICE raids that are tearing our communities apart,” the SEIU said in a statement.

Protesters also gathered in New York and Los Angeles in response to Trump’s latest ban on travellers from 12 countries, a policy critics have decried as racist.

Speaking at a protest in New York City on Monday, Murad Awawdeh, president of the New York Immigration Coalition, said the policy was “a continuation of the Muslim and travel ban under the first Trump administration, which separated families and harmed our communities”.

The policy, he said, was creating “an immense amount of fear”.