Pope Francis at the Zayed Sports City Stadium in Abu Dhabi. Image Credit: AFP

Vatican City: Pope Francis has defrocked a former cardinal in a first for the Catholic church over accusations American Theodore McCarrick sexually abused a teenager 50 years ago, a Vatican statement said Saturday.

McCarrick, 88, who resigned from the Vatican's College of Cardinals in July, is the first cardinal ever to be defrocked for sex abuse.

He was found guilty in January by a Vatican court for sexually abusing a teenager, a decision confirmed by the pope in February, with no further recourse, according to the statement.

The announcement marks a spectacular fall from grace for the previously influential cardinal and comes ahead of a Vatican conference from February 21-24 bringing together bishops from around the world to discuss protecting children within the Church

Sex abuse scandals around the globe, and most recently in the United States and Chile, have shaken the church, with Pope Francis promising a policy of "zero tolerance" even for high-ranking church members.

McCarrick, former archbishop emeritus of Washington, was barred from practising as a priest in July last year, after which he resigned his honorary title of cardinal. He currently lives in Kansas.

The Vatican in 2017 asked the New York archbishopric to investigate the powerful cardinal after a man accused McCarrick of having abused him in the 1970s.

McCarrick was known for having sex with adult seminarians before he was accused of sexually abusing at least one teenager.

Prosecutors in the US state of Pennsylvania last year found 300 priests were involved in child sexual abuse since the 1940s, crimes that were covered up by a string of bishops.