VATICAN CITY — Pope Francis' ninth night in hospital was peaceful, the Vatican said Sunday, the day after revealing the 88-year-old was in a "critical" condition.

The pope had on Saturday suffered a prolonged respiratory attack and required blood transfusions, the Vatican said that evening, while adding that he was alert and sitting in a chair.

"At the moment the prognosis is reserved," the Saturday statement had concluded, sparking widespread alarm about the leader of the world's almost 1.4 billion Catholics.

Sunday morning's update from the Vatican was brief, saying: "The night passed peacefully, the pope rested."

A Vatican source later said that unlike earlier in the week, the Argentine pontiff had not eaten breakfast, nor had he read the newspapers.

Francis, head of the Catholic Church since 2013, was initially admitted to Rome's Gemelli hospital on Feb. 14 with bronchitis, but it developed into double pneumonia.

Doctors had on Friday confirmed he was "not out of danger" but said he was slightly improved — building hopes for a recovery that were swiftly dashed.

Suffering more

"The Holy Father's condition continues to be critical, therefore, as explained (Friday), the pope is not out of danger," the Vatican said on Saturday evening.

It said Francis continued to be alert and "spent the day in an armchair even if he was suffering more than" the day before.

It said he had on Saturday morning suffered a "prolonged asthmatic respiratory crisis, which also required the application of high-flow oxygen."

Daily blood tests also "showed thrombocytopenia, associated with anemia, which required the administration of blood transfusions," it added.

Thrombocytopenia is a condition that occurs when the platelet count in someone's blood is too low, which can cause trouble stopping bleeding — and can be life-threatening.

Blood or platelet transfusions, delivered via an intravenous (IV) line into a blood vessel, are given to people who are either bleeding heavily or at very high risk of bleeding, according to the US National Institutes of Health (NIH).

"The pope gets worse," headlined Italy's Corriere della Sera newspaper on Sunday morning, while La Repubblica described it as the "darkest day" at the Vatican.

"The situation is becoming more worrying," Fabrizio Pregliasco, a leading Italian virologist, told La Stampa daily, adding that "the next few hours and days will be crucial."

The Vatican had already confirmed Francis would not deliver his usual weekly Angelus prayer on Sunday, saying the text would be published, as it was last weekend.

The pontiff has delivered the prayer in the past from the balcony of the Gemelli, where he is staying in a special papal suite on the 10th floor.

A senior prelate was also brought to replace Francis in celebrating a Sunday morning mass for the Jubilee 2025, a special year of Catholic celebrations. "Even though he is in a hospital bed, we feel him close to us," Rino Fisichella said before reading out the homily at St. Peter's Basilica, offering prayers for Francis in this "moment of trial."

The cardinal vicar of Rome, Baldo Reina, also urged believers to join him at a Mass on Sunday evening in the Basilica of St. John Lateran, calling on God to give Francis "the necessary strength."