Pope Francis on Sunday apologized for having to postpone his trip to Africa in July because of his knee pain, and vowed to reschedule it “as soon as possible.”

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

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 Vatican announced June 10 that due to treatment for his knee pain, the trip had to be put off. 

Pope Francis addressed the postponement in remarks after his daily Angelus reflection for pilgrims gathered in St. Peter’s Square on June 12 for Trinity Sunday.

“And now I would like to address the people and authorities of the Democratic Republic of Congo and South Sudan,” he began.

“Dear friends, with great regret, due to problems with my leg, I have had to postpone my visit to your countries, planned for the first days of July. I truly feel great sorrow for having had to postpone this trip, which means so much to me. I apologize for this,” he said.

“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 pope concluded.

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