VATICAN CITY (AP) — Pope Francis has defrocked the Chilean priest at the center of the global sex abuse scandal rocking his papacy, invoking his "supreme" authority to stiffen a sentence originally handed down by the Vatican in 2011.

In a statement Friday, the Vatican said Francis had laicized the 88-year-old Rev. Fernando Karadima, who was originally sanctioned to a lifetime of "penance and prayer" for having sexually abused minors.

The "penance and prayer" sanction has been the Vatican's punishment of choice for elderly priests convicted of raping and molesting children. It has long been criticized by victims as too soft and essentially an all-expenses-paid retirement.

The Vatican didn't say what new evidence, if any, prompted Francis to re-evaluate Karadima's original sanction and impose what clergy consider the equivalent of a death sentence.