Concern over the health of the Vatican chief is growing after a report said that Pope Francis has brain tumour.

The report has come three months after the pope once again indicated that he had "two to three years" more to live. Though Papal has strongly hit out against the Italian newspaper Quotidiano Nazionale for the "totally unfounded" claim, the publication has said that they stand by their story.

Quotidiano Nazionale carried a front page story on Wednesday - The Pope is Sick - in which it said that a Japanese doctor and his team from Tuscany has secretly visited Vatican to examine the pope "some months ago".

The report said that the 78-year-old Argentine pontiff was diagnosed with "a small dark spot on the brain," but said that it was a curable tumour. 

Vatican has launched a salvo of denials denouncing the article as "a grave act of irresponsibility, absolutely inexcusable and unconscionable" according to Reuters. But Pope on at least two occasions has predicted his own death.

In August, while talking to a group of journalists onboard the papal plane, Pope Francis indicated that he may have only "two or three years" to live and hinted that he is considering an early retirement.

The pontiff made the statement while talking to the media on a flight back to the Vatican from South Korea. A report in The Guardian had said that the Pope made a chopping gesture with his hand and whistled after making the statement, as if to convey that death comes sooner or later to everyone.

In a televised interview in March, Francis on the second anniversary of his election said that his pontificate would be short, according to Reuters.