Pope apologises over postponed trip to Africa

Pope Francis on Sunday reiterated his apology over having to postpone a trip to Africa in July on doctors' orders because of knee problems.

Speaking to the faithful in St Peter's Square, the pontiff said he felt "great regret" after mobility issues caused him to cancel his trip to Congo and South Sudan.

The pope has been using a wheelchair for 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.