The Vatican has placed its former ambassador to the Dominican Republic, Jozef Wesolowski, under house arrest on charges of sexually abusing children.
The former archbishop was defrocked in June after a Church tribunal found him guilty of abusing Dominican boys.
He will now be tried by a Vatican criminal court, becoming its highest official to face abuse charges there.
Wesolowski, who is originally from Poland, served as a papal envoy to the Dominican Republic for five years.
A Vatican spokesman said the arrest reflected Pope Francis's wish "that such a grave and delicate case be handled without delay, with the just and necessary rigour".
Pope Francis has pledged a crackdown on clerics and employees of the Church who exploit minors, comparing their actions to a "satanic mass".
Last year, he strengthened the Vatican's laws against child abuse.
The Vatican spokesman said the decision to place Wesolowski under house arrest, rather than hold him in a police cell, was taken on account of his health.
Wesolowski is expected to go on trial later this year.