The Vatican says Pope Francis has developed bilateral pneumonia, after new tests showed a further complication in the condition of the 88-year-old pope.

The 88-year pontiff has been suffering from a respiratory infection for more than a week and was admitted to Rome's Gemelli Hospital on February 14.

Pope Francis, who remains hospitalized, has bilateral pneumonia, the Vatican said on Tuesday. The term simply means pneumonia in both lungs, said Dr. James Musser, director of the center for infectious diseases at the Houston Methodist Research Institute.