STORY: The pope, 85, has suffered a flare-up of pain in the right knee in addition to a long-time case of sciatica, which also causes pain in the legs.
After greeting crowds from the popemobile in St. Peter's Square which drove him to the rear of the platform facing the crowd, he walked slowly while holding the arm of two aides, limping as he approached his seat about 11 yards away.
At the end of the audience, the pontiff struggled to stand up from the chair and was again helped by two aides back to the popemobile.
On May 5 the pontiff used a wheelchair in public for the first time and has used one since during private and public audiences.
Francis' health has forced the postponement of a trip to Lebanon next month but he is still due to make two trips in July, one to South Sudan and the Democratic Republic of Congo and the other to Canada.