Pope Francis, who has had trouble walking due to leg and knee pain, suspended activities on Friday for medical checks, the Vatican said.

The checks were taking place at the Vatican's medical facilities, spokesman Matteo Bruni said, explaining why there were no activities or audiences listed on Francis' public calendar for the day.

The 85-year-old pope suffers from sciatica in the right leg and recently has had a flare-up of pain in his right knee, causing him to limp more pronouncedly and to sit during some activities.

He read most of his Easter Sunday address from the balcony of St. Peter's Basilica sitting down. The day before, he attended but did not preside at an Easter vigil service, sitting during most of it.    

Saturday is the feast of St. George, which is a holiday in the Vatican because it is the pope's name day. He was born Jorge Mario Bergoglio and took the papal name Francis when he was elected in 2013.

Although he may carry out limited activities on Saturday, this would potentially give him more time to rest ahead of a Mass in St. Peter's Basilica scheduled for Sunday.