Pope Francis sharply criticized U.S. President Donald Trump's immigration crackdown in an unusual open letter to America's Catholic bishops on Tuesday, saying criminalising migrants and taking measures built on force "will end badly".

Pope Francis issued a clarion call to U.S. Catholics Feb. 10 to reject the anti-immigrant narrative of the Trump administration.

In the letter, the pope said the criminalization of migrants and the mass deportations planned by the U.S. government are dangerous and called the country's current immigration policies a “major crisis.