Pope Francis looks on during the weekly general audience on January 12, 2022 at Paul-VI hall in The Vatican. The 85-year-old pontiff made scathing remarks during his annual "state of the world" address to diplomats, enunciating "cancel culture" during a long speech on January 10, 2022. Photo: AFP

Pope Francis said Sunday he hoped to visit the Democratic Republic of the Congo and South Sudan as soon as possible, after canceling an upcoming visit due to a knee problem.

"Dear friends, with great regret, due to problems with my leg, I have had to postpone my visit to your countries," the 85-year-old said after delivering his weekly Angelus prayer in St Peter's Square.

"I truly feel great sorrow for having had to postpone this trip, which means so much to me. I apologize for this." 

"Let us pray together that, with the help of God and medical attention, I will be able to be with you as soon as possible. Let us be hopeful!"

The Vatican on Friday announced that the trip planned for July 2 to 7 would be rescheduled, although no new date was set.

"At the request of his doctors, and in order not to jeopardize the results of the therapy that he is undergoing for his knee, the Holy Father has been forced to postpone," spokesperson Matteo Bruni said.

Francis has been suffering from pain in his right knee in recent weeks and last month relied on a wheelchair for the first time at a public event. 

He has canceled numerous engagements - a scheduled trip to Lebanon in June was postponed - and has sometimes been seen struggling to walk. 

The Vatican has not said officially what the problem is, although sources have told AFP he has chronic arthritis.

The pope himself has also spoken of an injured ligament in his knee. 

Also on Sunday, the pope urged the world not to forget about the conflict in Ukraine.

AFP