Pope Francis has shared his first spoken message since he was admitted to hospital nearly three weeks ago.

Francis, 88, thanked well-wishers ‘from the bottom of my heart’ in an audio recording played during a nightly prayer service for the pope in St Peter’s Square at the Vatican this evening.

Speaking in his native Spanish, and pausing for breath every few words, he said: ‘I thank you from the bottom of my heart for your prayers in the Square for my health.

‘May God bless you.’

It came shortly after the Vatican said Francis remained stable on Thursday and did not have any new episodes of respiratory crisis.

Hearing Francis’s voice is another encouraging sign after his doctors said they would not issue another medical bulletin until Saturday ‘considering the stability of the clinical picture’.

But they repeated their regular caveat that the Argentine’s prognosis remains ‘guarded’, meaning he is still not out of the woods.

Francis was admitted to Gemelli hospital on February 14 with a severe respiratory infection that has required continuously evolving treatment.

The tone of the updates from the Vatican has been more upbeat in recent days, following what was described as two episodes of ‘acute respiratory insufficiency’ on Monday.

On Thursday, the Vatican said the pope had been able to work between receiving his treatments and taking rest.

It also said the pontiff, who has used a wheelchair in recent years due to knee and back pain, had continued with some physical therapy to help with mobility, which first started on Wednesday.

Monday’s respiratory episodes had required Francis to use non-invasive mechanical ventilation, which involves placing a mask over the face to help push air into the lungs.

The pope is now only receiving ventilation at night, said the Vatican. During the day, he receives oxygen via a small hose under his nose.

Francis has not been seen in public since entering hospital, his longest such absence since his papacy started 12 years ago.

His doctors have not said how long the treatment might last.

The pope, who is known to work himself to exhaustion, has continued to work from hospital.

On Thursday, the Vatican announced the appointments of two bishops that would have required his approval.

The pope has experienced several bouts of ill health over the last two years and is prone to lung infections because he had pleurisy as a young adult and had part of one lung removed.

Double pneumonia is a serious infection in both lungs that can inflame and scar them, making it difficult to breathe.