Pope Francis had another "peaceful night" at Rome's Gemelli hospital and was resting on Wednesday morning as he continues to receive treatment for double pneumonia, the Vatican said.

Francis, 88, has been in critical condition for several days and he has remained absent from several regular appearances. The church has encouraged worshippers around the world to pray for his health.

Eleven days after the pope was hospitalized, speculation is mounting and prayers for his recovery verge on a vigil.