Spokesman Matteo Bruni said in a statement that a CT scan at a Rome hospital on Saturday excluded pneumonia but had detected inflammation in the pope's lungs that caused breathing difficulties.

"The pope's condition is good and stable, he does not have a fever and his respiratory condition is decidedly improving," Bruni said.

"To facilitate the pope's recovery, some important engagements that were scheduled for these days have been postponed so that he can dedicate his time and energy (to recovery)".

Bruni added that Francis, 86, would continue to carry out "easier", institutional tasks, his condition permitting.

The Vatican later said the pope went ahead with a planned audience for the president of Paraguay, Santiago Peña Palacios, at the Vatican guest house where the pope lives in a suite of rooms. Audiences for heads of state normally take place in the Apostolic Palace, a separate building on the Vatican grounds

One part of one of the pope's lungs was removed when Francis was a young man in his native Argentina.

Francis is due to travel to Dubai on Friday to attend the U.N. climate change conference. Bruni's statement did not mention the trip, apparently indicating that it was still on.

For his weekly blessing and message on Sunday, Francis appeared seated in the chapel of his residence instead of in St. Peter's Square, while an aide read the pontiff's message.

When he raised his right hand a bandage holding an IV tube used to administer the antibiotics was visible.

Earlier this month Francis skipped reading a prepared speech for a meeting with European rabbis because he had a cold, but he appeared to be in good health during a meeting with children hours later that day.

In June he had surgery on an abdominal hernia, spending nine days in hospital. He appears to have recovered fully from that operation.