US President Donald Trump on Friday said he would deploy National Guard troops to Memphis, Tennessee, in the latest stage of his crime crackdown that critics say is authoritarian.

The Republican president has sent military forces into Los Angeles and Washington, and pledged to expand orders to other cities including Chicago and New York.

Some locals have welcomed the patrols, while other residents have complained of the soldiers being unsuitable for tackling crime and of the operation largely targeting immigrants.

"We're going to Memphis. Memphis is deeply troubled. The mayor is happy, the governor is happy... We're going to fix that just like we did Washington," Trump told Fox News.

Memphis, a Black-majority city, has a Democratic mayor, while Tennessee state has a Republican governor.

The Trump administration this week launched a new immigration enforcement operation in Chicago to target what it called the "worst of the worst criminals."

Trump has repeatedly also threatened to send National Guard troops into the city, sparring with Illinois state Governor JB Pritzker, a Democrat, in social media posts.

The president has claimed troop deployments and deportation raids in Washington and Los Angeles have saved the cities from immigrant crime -- one of his key election pledges. (AFP)