Donald Trump's rumbling conflict with the judiciary burst into open confrontation on Tuesday as Supreme Court Justice John Roberts issued a rare public rebuke of the U.S. president over his call for the impeachment of a federal judge.

"For more than two centuries, it has been established that impeachment is not an appropriate response to disagreement concerning a judicial decision," Roberts said in a brief statement. "The normal appellate review process exists for that purpose."

Roberts's extraordinary rebuke of the president came after Trump called for the impeachment of District Judge James Boasberg, who ordered the suspension over the weekend of deportation flights of alleged illegal migrants.