A US appeals court has ruled that President Donald Trump could continue control of National Guard troops in Los Angeles, over the objections of California Governor Gavin Newsom.

In a unanimous 38-page ruling on Thursday, the three-judge panel said Trump's "failure to issue the federalization order directly 'through' the Governor of California does not limit his otherwise lawful authority to call up the National Guard".

Trump was within his rights when he ordered 4,000 members of the National Guard into service for 60 days to "protect federal personnel performing federal functions and to protect federal property", the judges wrote.

In a post to Truth Social Thursday night, Trump celebrated the decision and called it a "BIG WIN."

"All over the United States, if our Cities, and our people, need protection, we are the ones to give it to them should State and Local Police be unable, for whatever reason, to get the job done," he wrote.

Last week, a lower court judge had ordered Trump to return control of the California National Guard to Newsom, saying the president's decision to deploy them to protest-hit Los Angeles was "illegal".

Newsom hailed the earlier decision saying Trump "is not a monarch, he is not a king, and he should stop acting like one".

Trump, who has repeatedly exaggerated the scale of the unrest, also sent 700 US Marines to Los Angeles despite the objections of local officials, claiming that they had lost control of the "burning" city.

It was the first time since 1965 that a US president deployed the National Guard over the wishes of a state governor.

Trump appointed two of the judges on the US Court of Appeals for the Ninth Circuit panel, and former president Joe Biden appointed the third, the New York Times reported on Thursday. (AFP)