The Trump administration’s immigration crackdown is under way today - targeting migrant families in major cities across the country.

Sweeps had been expected to start on Sunday, but New York City mayor Bill de Blasio tweeted on Saturday that the Immigration and Customs Enforcement (ICE) agency had already taken action in New York.

He said they had targeted Brooklyn’s Sunset Park and parts of Harlem, but had been unsuccessful in detaining anyone. He says he has refused too co-operate with ICE.

Immigrant communities have been on edge since President Donald Trump's administration announced plans for the operation, with some going to extreme lengths to avoid being deported.

There were reports of some families stockpiling food and drawing the curtains, while others pinned notices to the inside of their front doors with legal advice on what to do if enforcement agents came knocking.

Immigrants who've been given orders to leave the country are government targets in at least 10 cities.

Advocates are coaching them on their rights, including instructions not to respond if agents knock on the door unless shown a warrant signed by a judge.

The American Civil Liberties Union filed a pre-emptive lawsuit Thursday that aims to protect asylum seekers. Activists held demonstrations and advocates coached immigrants on their rights.

The Trump administration says the coordinated action will target about 2,000 people with final deportation orders in major cities, including Chicago, Los Angeles, New York and Miami.