Pope Francis said Wednesday that former pontiff Benedict XVI, 95, whose health has steadily been deteriorating, is "very ill" and he is praying for him.

"I would like to ask all of you to pray a special prayer for Pope Emeritus Benedict," Francis said at the end of his general audience.

He called on people to "remember him, because he is very ill, asking the Lord to console and support him".

Benedict, who in 2013 became the first pontiff to resign in six centuries, has almost entirely withdrawn from public view.

The few photographs that have emerged of him have shown him to be in increasingly frail health.

Back in 2013, he had cited his declining physical and mental health in his decision to become the first pope since 1415 to give up the job as head of the worldwide Catholic church.

In April, Benedict's long-time secretary, Archbishop Georg Gaenswein, told Vatican News the ex-pope was "physically relatively weak and fragile", but "in good spirits".