Pope Francis has remained stable after suffering two episodes of respiratory failure on Monday.

In its nightly update, the Vatican said the Pope did not present any further episodes of respiratory failure or bronchospasm.

"He remained afebrile, always alert, cooperative with therapies and well-oriented", the statement said.

The 88-year-old pontiff has been in hospital since mid-February undergoing treatment for pneumonia.

After Monday's episodes, the Pope had begun using an oxygen mask and ventilator to assist his breathing.

It was the second time the mechanical intervention had been used, after spending two days on the ventilator following an "isolated" breathing crisis involving vomiting on Friday, the Vatican said.

In Tuesday's update, the Holy See said Pope Francis had switched back to high-flow oxygen therapy.

During the day he alternated prayer and rest and this morning he received the Eucharist, it added.

Pope Francis is due to miss the procession and mass on Wednesday that marks the first day of Lent, the six-week period leading to Easter.

He has been unable to deliver his traditional Angelus prayer in person on each of the last three Sundays.

The Pope was admitted to hospital on 14 February after experiencing breathing difficulties for several days.

He was first treated for bronchitis before being diagnosed with pneumonia in both lungs.

The pontiff is particularly susceptible to pneumonia, an infection of the lungs that can be caused by bacteria, viruses or fungi, after he contracted pleurisy – an inflammation of the lungs – as a young man and had a partial lung removal.

Vatican sources stress, as they have all along, that the Pope's condition remains complex – his doctors remain cautious - and he is not out of danger.