Pope Francis has hinted that he could resign from his post, like Benedict XVI in 2013, and joked about his own death saying that in "two or three years" he would be off to the Father's house.

The 77 year-old pontiff, who was chatting with reporters on an Alitalia 4000 plane while returning from his successful South Korea trip, said he could handle popularity "more naturally" now although at the beginning it had "scared me a little".

Referring to his popularity, which was clear also from his Korean visit in which hundreds of thousands of people gathered for his open-air mass, the Argentinian pope said that it sees it as "the generosity of the people of God".

"I try to think of my sins, my mistakes, not to become proud. Because I know it will last only a short time. Two or three years and then I'll be off to the Father's house," he joked, according to AFP.

Then, he reportedly made a chopping gesture with his hand and whistled to suggest that death comes for everyone.

He added that Benedict XVI "opened a door" with his retirement, something no Pope has ever done for 600 years, and suggested that it could be a possibility "even if it does not appeal to some theologians".

Retirement a possibility

Rumours about Pope Francis' health raised concerns in June after he cancelled a number of engagements due to minor ailments. The pope, who suffers from sciatica, or leg pain caused by a pinched nerve, scrapped at least four appointments in the past months.

Veteran Vatican correspondent Edward Pointin noticed that since his election in March 2013, the Pope has kept up "a punishing schedule of engagements". Unlike his predecessors John Paul II and Benedict XVI, Francis did not spend the summer holidays in Castel Gandolfo outside Rome, but will instead be working from his offices in the Vatican.

The pope seems to be aware of his failing health. During a visit to the Sant Egidio charity in Rome's Trastevere neighbourhood, the pope asked the crowds to pray for him. "My work is unhealthy, extraordinary work and I need prayer," he said.

In the flights to the Vatican, he admitted having "some nerve problems" which required treatment, but lightheartedly added: "Must treat them well, these nerves, give them mate [Argentinian stimulant tea] every day," he poked fun again.