WASHINGTON, United States (AFP) — Hundreds of migrants in the United States (US) were arrested Thursday and others flown out of the country on military aircraft as the White House said President Donald Trump’s promised deportation operation had started.

The crackdown came as Trump prepared to head to California and North Carolina on Friday, where natural disasters have turned into political footballs, in his first trip since his return to office.

And on another whirlwind day in his first week as president, Trump told Fox News he would “rather not” impose tariffs on China despite repeated vows to hit America’s biggest economic rival with hefty import levies.

The Republican also said he would seek to rekindle his diplomatic relationship with Kim Jong Un, calling the North Korean leader he has met three times a “smart guy”.

White House Press Secretary Karoline Leavitt said Trump’s administration on Thursday “arrested 538 illegal immigrant criminals,” adding “hundreds” were deported by military aircraft.

“The largest massive deportation operation in history is well underway,” she said in a post on social media platform X.

Trump promised a crackdown on illegal immigration during the election campaign and began his second term with a flurry of executive actions aimed at overhauling entry to the United States.

UN Rights Office Spokeswoman Ravina Shamdasani said in Geneva on Friday that, while countries “are entitled to exercise their jurisdiction along their international borders,” they must remember that “the right to seek asylum is a universally recognised human right”.

On his first day in office, Trump signed orders declaring a “national emergency” at the southern border and announced the deployment of more troops to the area, vowing to deport “criminal aliens”.

There are an estimated 11 million undocumented migrants in the United States, according to the Office of Homeland Security Statistics.

The Democratic mayor of the city of Newark, New Jersey, Ras Baraka, said in a statement on Thursday that Immigration and Customs Enforcement (ICE) agents “raided a local establishment… detaining undocumented residents as well as citizens, without producing a warrant”.

Baraka said one of those detained during the raid was a US military veteran.

ICE announced “538 arrests” and “373 detainers lodged” in an “enforcement update” on X.

ICE lodges detainers for non-citizens who have been arrested on criminal charges and who the agency believes can be deported under the law in order to keep them in custody.