Pope Francis has cancelled a planned July trip to Africa on doctors’ orders because of ongoing knee problems, the Vatican said on Friday, raising further questions about the health and mobility problems of the 85-year-old pontiff.

The Vatican said the July 2-7 trip to Congo and South Sudan would be rescheduled “to a later date to be determined”.

“At the request of his doctors, and in order not to jeopardise the results of the therapy that he is undergoing for his knee, the Holy Father has been forced to postpone, with regret, his Apostolic Journey to the Democratic Republic of Congo and to South Sudan, planned for 2 to 7 July, to a later date to be determined,” the Vatican said in a statement.

Francis has been using a wheelchair for about a month due to strained ligaments in his right knee that have made walking and standing difficult and painful.

He has refused so far to get surgery, and has instead received injections, kept the knee as immobile as possible and walked with a cane or the help of an aide.

Questions had swirled for months about Francis’ ability to negotiate the Africa journey, which would have been taxing for the pope even without the knee problems. Yet as recently as this week, plans were proceeding for the trip, with the Vatican releasing the names of accredited journalists who were due to fly on the papal plane.

Francis had been due to visit South Sudan with the Archbishop of Canterbury and the head of the Church of Scotland to make a joint, ecumenical appeal for peace. Such a trip had been discussed as early as 2017 but security concerns kept postponing it.

The Rev. John Gbemyoro, an official with the Sudan and South Sudan Catholic Bishops’ Conference, said Friday’s news dashed expectations of Christians in both countries.

“We don’t love to hear it,” he told The Associated Press. “But we are asking God to heal him quickly because we still need him to come to South Sudan.”

Archbishop of Canterbury Justin Welby and the moderator of the Church of Scotland, Rt Rev Iain Greenshields, said they were praying for Francis and regretted the trip would again be postponed.

“I continue to pray for the people of South Sudan in their challenges and hopes for peace, and look forward to this historic visit at a later date,” Mr Welby tweeted.

The Congolese government said it wished Francis a prompt recovery and assured him that Congo still awaits him “for his visit under the sign of peace and reconciliation in Jesus Christ”.

Francis also has a July 24-30 visit to Canada scheduled; the Vatican statement on Friday said nothing about that trip. Vatican spokesman Matteo Bruni would only say that the pope’s other commitments were confirmed.

The pope has told friends he does not want to undergo knee surgery, reportedly because of his reaction to anaesthesia when he had 33cm of his large intestine removed in July 2021.

Speculation has swirled about the future of the pontificate because of Francis’ knee problems, his decision to create 16 new voting-age cardinals in August, and his plans to pay homage that same month to a 13th century pope who resigned, Celestine V.

But Francis has given no indication he wants or plans to resign. Vatican watchers say a papal resignation now would be unthinkable given that Francis’ 95-year-old predecessor, Emeritus Pope Benedict XVI, is still alive.