Pope Leo waves and smiles to the crowds after reaching the window overlooking St Peter’s Square unaided at the Vatican. (EPA Images pic)VATICAN CITY: Pope Leo called for an end to the violence in Yemen on Sunday, as he addressed the faithful from the window over St Peter's Square less than two weeks after having surgery for lung cancer.

The 71-year-old pontiff said he was particularly concerned about the humanitarian situation in the southwestern Yemeni city of Taiz, "where the population suffers due to the lack of food, water and medical assistance".

He waved and smiled to the crowds after reaching the window unaided — the same spot where he announced on Oct 11 that he would have an operation to remove a small growth on his lung, in the first health scare of his papacy.