Pope Francis said in an interview Friday he will ask God's advice when the time comes to consider retiring like his 87-year-old predecessor Benedict XVI.
Benedict last year became the first pope to resign since the Middle Ages, retiring from public life to live in a former monastery inside the Vatican City walls.
"Since we live longer, we get to an age at which we can no longer carry on with things," the 77-year-old Francis said in a wide-ranging interview with the Vatican correspondent of Barcelona-based daily La Vanguardia.
The pontiff said Benedict made a "great gesture" when he left his position as leader of the Church, opening the door to the possibility of emeritus popes.
"I will do the same as he did: ask the Lord to show me when the moment comes and tell me what to do, and he will tell me for sure," said the spiritual leader of the world's 1.2 billion Roman Catholics.
The pope alluded to his mortality when admitting that he took a risk when he avoided riding in the closed-in "popemobile".
"I cannot greet the people and tell them I love them inside a sardine can, even if it is glass," he said, describing the protection as a "wall".
"It is true something could happen to me but let's be realistic, at my age I do not have much to lose," the pope said.
Following his first visit to the Middle East as pope last month, the pontiff criticised fundamentalism in Christianity, Islam and Judaism as a form of violence.
"A fundamentalist group, even if it kills no one, even it strikes no one, is violent. The mental structure of fundamentalism is violence in the name of God."
Asked about religious violence in the Middle East, Francis, who made his first visit to the region as pope last month, said it was a "contradiction".
"Violence in God's name does not fit with our times. It is something old. With historical perspective, we have to say that we Christians, at times, have practiced it," he was quoted as saying.
"Today it is unimaginable."
- 'It's madness' -
Anti-Semitism, the pope said, seemed to be linked more to the right-wing than to the left, though he could not explain why.
"And it still continues. We even have people who deny the Holocaust, which is madness."
Pope Francis said he was worried about drives for independence in lands such as Scotland and Catalonia.
The Argentine pontiff said separatism was understandable in cases such as former colonies and the former Yugoslavia, but said these models did not apply in all cases.
"Any division worries me," he said.
He cited cases such as Scotland, the northeastern Spanish region of Catalonia and the northern Italian region of Padania, saying these did not have the same history of "forced unity".
"There are obviously peoples with cultures so diverse that they cannot be stuck together even with glue. In the case of Yugoslavia that is very clear but I wonder where it is so clear in other cases of peoples who until now have been together," he was quoted as saying.
Pope Francis reserved harsh criticism for the global economic system, saying it leaves millions of young unemployed, puts money ahead of people and survives on the profits of war.
"It's madness," the pope said.
"We discard a whole generation to maintain an economic system that no longer endures, a system that to survive has to make war, as the big empires have always done," Francis said.