Nobel Peace Prize laureate, Malala Yousafzai described US President Donald Trump's policy to separate children of illegal immigrants from their families as “cruel” during her first visit to South America to promote girls’ education.

More than 2,300 children were separated from their parents after the Trump administration began a “zero tolerance” policy on illegal immigrants in early May, seeking to prosecute all adults who cross the border illegally from Mexico into the US.

Trump stopped separating families last month following public outrage and court challenges.