President Donald Trump says he's considering deploying the National Guard to cities such as Chicago and New York as part of his crack down on crime, homelessness and illegal immigration.

National Guard units are already patrolling Washington DC with firearms.

Trump also deployed federal troops to Los Angeles earlier this summer to deal with protests over the administration’s immigration crackdown.

National Guard troops are typically deployed with the permission of state governors in response to emergencies and natural disasters.

Some previous National Guard deployments have restored peace after violent crackdowns from local law enforcement or vigilante violence, but sometimes troops have intensified tensions in communities.

Almost five years ago, California Governor Gavin Newsom deployed thousands of National Guard troops to quell protests over racial injustice inspired by the death of George Floyd.

National Guard troops were also deployed in Los Angeles in 1992 after riots broke out following the acquittal of white police officers who were filmed severely beating Rodney King.

In 1956, the governor of Tennessee assigned National Guard troops to help enforce integration in Clinton, Tennessee, after white supremacists violently resisted federal orders to desegregate.

Trump has repeatedly described some of the nation’s largest cities — run by Democrats, with Black mayors and majority-minority populations — as dangerous and filthy.

Illinois Gov. JB Pritzker, a Democrat, said there is no emergency warranting the deployment of National Guard troops in Chicago and said Trump is "attempting to manufacture a crisis"