WASHINGTON (AFP) - President Donald Trump sought to reassure 800,000 migrants they are safe in the United States for at least the next six months, days after stripping their protection from deportation.

Trump this week revoked an Obama-era amnesty for migrants who were brought to the United States illegally as children. He has since faced a massive political backlash.

In the face of criticism from religious groups, business leaders, Democrats and Republicans, Trump on Thursday (Sept 7) tried to reassure those set to lose so-called "DACA" residency permits that a grace period would be respected.

"For all of those (DACA) that are concerned about your status during the 6 month period, you have nothing to worry about - No action!" he said.

It is unclear what will happen to the roughly 800,000 people who benefited from the amnesty after that period and as their residency permits expire over the next two years.

Trump has sent mixed messages about the programme he ended, calling it illegal, but asking Congress to make it law permanently.