VATICAN CITY - Former Pope Benedict is in a "stable" condition, the Vatican said on Friday, amid continued concern for the health of the 95-year-old retired pontiff.

Benedict had a peaceful night and on Thursday afternoon participated in a Mass celebrated in his room, Vatican spokesman Matteo Bruni said.

"At the moment his condition is stable," he added.

Benedict is being cared for in a former convent inside the Vatican, where he has been living since 2013, when he became the first pope in about 600 years to resign instead of ruling for life.

Pope Francis first disclosed that Benedict's health had seriously deteriorated on Wednesday, when he said that his predecessor was "very sick" and called for special prayers for him.

(Reporting by Alvise Armellini, editing Federico Maccioni and Tomasz Janowski)