Bishops who covered up for abuse guilty of wrongdoing: Pope Francis

Aboard the papal plane: Pope Francis has defended his words of consolation to US bishops over the priest sex abuse scandal but said - for the first time - that those who covered up for abusers are guilty of wrongdoing.

Francis spoke en route to Rome after his first-ever visit to the United States, where he met with five abuse survivors and warned bishops that they would be held accountable for protecting their flocks.

Francis said "those who covered this up are guilty."

While the Vatican has cracked down on priests who rape and molest children in recent years, it has long been accused of turning a blind eye to the bishops who moved abusers around rather than report them to police.

Francis has created a Vatican tribunal to prosecute these bishops.