Pope Francis remained in a critical condition but was showing signs of a “slight improvement”, the Vatican said on Monday.

The 88 year-old, who has pneumonia in both lungs, was spending his 11th night in Rome’s Gemelli Hospital on Monday night, making it his longest hospital stay in nearly 12 years leading the Catholic Church.

Addressing global concern over his health, the Vatican said in its evening bulletin that “the critical clinical conditions of the Holy Father demonstrate a slight improvement”. It warned that doctors would not offer a prognosis, however.

“Today there were no episodes of asthmatic respiratory attacks; some laboratory tests have improved,” it said, noting that Francis had worked in the afternoon after receiving the Eucharist in the morning.

The Pope was taken to hospital on Feb 14 with breathing difficulties and his condition has since worsened.