Hundreds of thousands of immigrants who were given special permission to come to the US will be told that they must leave the country immediately.

The Department of Homeland Security (DHS) said in a statement Thursday that Cubans, Haitians, Nicaraguans, and Venezuelans who were previously temporarily shielded from deportation will be emailed notices telling them to go.

The DHS said that more than half a million people from the four countries were allowed to remain in the US for two years under orders issued by former President Joe Biden.

The directive is expected to face legal challenges from opponents of the Trump administration's mass deportation programme.

During his time in office, Biden expanded the protection, which is called "humanitarian parole" and dates back to the Cold War, due to conditions in each of the four countries.

The DHS previously said that through the end of November 2024, a total of 531,670 people were granted permission to stay in the US under the programme, and that as a result, illegal crossings from citizens of the four countries had decreased by 98%.

It's unclear exactly how many people will be affected by the new directive, however, as some of the immigrants from those countries may have acquired legal status to remain in the US under other visa programmes.

The Biden administration had said the immigrants, who each required a US-based sponsor, were screened and vetted. However, the Trump administration disagreed.

DHS spokesperson Tricia McLaughlin called the Biden-era programme "disastrous" and in a statement said it opened the door for fraudulent claims and crime and it undercut American workers.

The programme became an issue during last year's presidential campaign, particularly when Trump and his allies focused attention on cities like Springfield, Ohio, which in recent years has seen a large influx of Haitian immigrants - many of whom were permitted to stay in the country under the programme.

Trump and others made inflammatory statements about Haitian immigrants eating pets, which were found to be lacking in evidence.

However, Trump's running mate, Vice-President JD Vance, defended what he described as "creating a story" to highlight high levels of immigration and what he called "the suffering of the American people."

President Trump cancelled Biden's order on parole with an executive order of his own shortly after he took office in January.

In May the Supreme Court upheld his suspension of the humanitarian parole programme while a legal battle continues in lower courts.

The DHS has promised travel assistance and a $1,000 "exit bonus" to migrants without legal permission to be in the US who voluntarily leave the country.