Donald Trump broke the law when he ordered thousands of National Guard be deployed to Los Angeles, a judge has ruled.

In a blow to Mr Trump’s federal crackdown, Judge Charles R Breyer on Tuesday found the deployment of soldiers and Marines, in response to anti-immigration protests this summer, violated the Posse Comitatus Act.

Judge Breyer’s ruling accused the Trump administration of “willfully” violating the law, saying it used troops for functions that were barred by their own training materials, refused to “meaningfully coordinate with state and local officials” and “coached” federal law enforcement agencies on the language to use when requesting assistance.

“These actions demonstrate that defendants knew that they were ordering troops to execute domestic law beyond their usual authority,” he wrote.

“The evidence at trial established that Defendants systematically used armed soldiers [whose identity was often obscured by protective armor] and military vehicles to set up protective perimeters and traffic blockades, engage in crowd control, and otherwise demonstrate a military presence in and around Los Angeles.”

The ruling came more than two months after Mr Trump controversially deployed the troops. The number of soldiers deployed has since dwindled from 4,000 to about 300 National Guard troops.