Pope Francis’ July trip to the African countries of the Democratic Republic of Congo and South Sudan has been postponed for health reasons, the Vatican said on Friday.

“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, with regret, his Apostolic Journey to the Democratic Republic of Congo and to South Sudan,” Vatican spokesman Matteo Bruni said on June 10.

The trip, planned for July 2-7, will be moved “to a later date to be determined,” the statement said.

Pope Francis was planning to spend July 2-5 in the Congolese cities of Kinshasa and Goma, and July 5-7 in the South Sudanese capital Juba.

The trip’s full program was published at the end of May.

The 85-year-old has been suffering from a painful inflamed ligament in his knee, limiting his ability to walk. He has been using a wheelchair during public appearances since last month.

He is still scheduled to visit Canada on July 24-29.