Pope Francis' health condition remains 'stable but complex'

Pope Francis's condition remains stable but complex, the Vatican said on Friday, as he reached three weeks in the hospital.

The Argentine pontiff, who released an audio message in Spanish on Thursday, has suffered several respiratory crises since his admission, most recently on Monday.

His audio message was broadcast to pilgrims in St Peter's Square and was the first time the world had heard the pope's voice since he was admitted to Rome's Gemelli hospital on February 14.

"I thank you from the bottom of my heart for your prayers for my health from the Square. I accompany you from here," Francis said, as he took labored breaths. "May God bless you and the Virgin protect you. Thank you."

A Vatican source insisted Francis wanted to speak in a language that would have a wider audience, playing down concerns that the pope was unable to muster the strength to speak in Italian, which is used for official Vatican business. 

The source confirmed the pope's status on Friday was "stable in a complex picture."

Pope getting respiratory and physical therpay

Francis currently switches between an oxygen mask at night and a cannula, a plastic tube tucking into the nostrils, delivering high-flow oxygen during the day. 

In an effort to move towards rehabilitation he has been getting respiratory therapy to improve his lung function since at least February 26. 

He is also receiving physical therapy to try to overcome the effects of his longest hospital stay since he became pope 12 years ago.

While the Vatican says Francis has spent long spells in an armchair, it is not clear if he can walk or stand unaided.

Vatican more transparent than before

Aiming for greater transparency, the Vatican has been publishing an update on how the pope slept every morning, followed by a more detailed medical bulletin each evening.

However, on Thursday "in view of the stability of the clinical picture," they said there would be no medical bulletin on Friday evening, with the next due on Saturday.

On Friday morning, the Vatican provided their usual brief update, saying Francis "passed a calm night and woke up shortly after 8:00am (CET)."

Francis's health has regularly led to speculation, particularly among his critics, as to whether he could resign like his predecessor, Benedict XVI.

Edited by: Wesley Dockery