VATICAN CITY: Pope Francis, continuing his recovery from life-threatening pneumonia, made a surprise visit on Saturday to his favourite Roman basilica, the Vatican press service said on Telegram.

It was a fourth unscheduled appearance in recent days for the 88-year-old pope -- including one at the Vatican's Saint Peter's Basilica on Thursday -- despite doctors urging him to rest.

Saturday saw him “pray before the icon of the Virgin” at Saint Mary Major, the press service said, on the eve of Palm Sunday, as Christians enter Holy Week culminating in Easter Sunday in a week’s time.

The Argentine pontiff last week made an appearance at Saint Peter's to greet faithful before Wednesday having an equally unexpected private audience with the visiting British royal couple of King Charles III and Queen Camilla -- a tete-a-tete which had initially been cancelled on doctors' orders.

Thursday saw him back at Saint Peter's to inspect renovation work.

Francis, leader of the world's 1.4 billion Catholics since 2013, returned to his quarters in the Vatican on March 23 after five weeks in Rome's Gemelli hospital to be treated for ver double pneumonia.

On Friday, the Vatican said his voice and mobility were improving, but warned it was too early to say if he will take part in Holy Week preparations which culminate on Easter Sunday in a week's time.

Even so, the Vatican said Friday that “the fact he is convalescing does not mean he cannot go out.”

However, Palm Sunday mass will be presided over by Cardinal Leonardo Sandri.