Former US president Barack Obama decried his successor’s decision to end an amnesty for 800,000 people brought to America illegally as children, describing it as "wrong," "self-defeating" and "cruel."

In a rare re-entry onto the political stage, Obama used a Facebook post to slam Trump's decision and call on Congress to step in.

"To target these young people is wrong -- because they have done nothing wrong. It is self-defeating -- because they want to start new businesses, staff our labs, serve in our military, and otherwise contribute to the country we love. And it is cruel," he wrote