Pope Francis remained in critical condition in an Italian hospital on Sunday, as officials shared that he is suffering from early-stage kidney failure amid his treatment for bilateral pneumonia.

Francis, who is currently staying at the Gemelli University Hospital in Rome, remains alert and attended Mass on Sunday, according to the Vatican. The pope has been fighting pneumonia and a complex lung infection since being hospitalized on Feb. 14.

The Holy See Press Office published a detailed statement about the 88-year-old pope's health on Sunday, noting that his condition "remains critical, but since [Saturday] evening, he has not experienced any further respiratory crises."

"He received two units of concentrated red blood cells with benefit, and his hemoglobin levels have risen," the report noted.

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"The thrombocytopenia remains stable; however, some blood tests show early, mild renal insufficiency [kidney failure], which is currently under control."

The Holy See also noted that Pope Francis is receiving oxygen and "remains alert and well-oriented."

"The complexity of the clinical situation and the necessary time for the pharmacological treatments to show results require that the prognosis remain reserved," the statement concluded. "This morning, in the apartment on the tenth floor, he participated in the Holy Mass, together with those who have been taking care of him during these days of hospitalization."

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The statement came after Pope Francis published a message of his own on X, thanking the international Catholic community for their prayers. He had suffered a prolonged asthmatic respiratory crisis on Saturday, a condition worsened by the fact that he had part of one of his lungs removed when he was younger.

"I have recently received many messages of affection, and I have been particularly struck by the letters and drawings from children," Pope Francis posted on X Sunday. "Thank you for your closeness, and for the consoling prayers I have received from all over the world!" 

"I urge you to continue your apostolate with joy and to be a sign of a love that embraces everyone, as the #GospelOfTheDay suggests," another post of his read. "May we transform evil into goodness and build a fraternal world. Do not be afraid to take risks for love!" 

The Associated Press contributed to this report.