Pope Benedict XVI had a secret operation three months ago to replace the batteries in his pacemaker but this did not influence his decision to resign, the Vatican has said.

"It was a routine operation. He already had a pacemaker. This had nothing to do with the decision of the Holy Father," Vatican spokesman Federico Lombardi said at a press briefing on Tuesday.

Al Jazeera's James Bays, reporting from New York, said the pope possibly made his decision to resign as early as last year following a trip to Cuba.

While the pope's heart troubles were widely known, the fact he had an operation so recently was only reported by Italian daily Il Sole 24 Ore a day after his resignation was announced.

The report fuelled speculation that the pope was resigning because of illness, even though he himself said he was resigning because his advancing age prevented him from carrying out his duties.

The newspaper report cited people close to the pope saying the operation had encouraged him to "question himself with simplicity and decisiveness over his capacity to guide the Ship of Saint Peter".

The 85-year-old pope had suffered a number of health-related incidents in recent years, although the Vatican has emphasised that he is not suffering from any major illness except for old age.

In 2009, the elderly pope broke his wrist while on holiday in the Alps when he slipped in the bath.

As Cardinal Joseph Ratzinger, he suffered a stroke that weakened his heart and briefly affected his eyesight and in a separate incident suffered a head wound for which he required stitches.

He also has arthritis in his hip, knees, and ankles, which affects his walking.

Vatican retirement

With speculation swirling about his future role, the Vatican's chief spokesman explicitly stated on Tuesday that Benedict will not influence the election of his successor.

"The pope will surely say absolutely nothing about the process of the election,'' Lombardi told reporters at a briefing. "He will not interfere in any way.''

Lombardi also said that after his February 28 abdication, "objects strictly connected'' with the papal ministry will be "terminated'.'

Among these is the papal ring, used as a seal for documents, which is smashed upon a pope's death.

The Vatican has already picked out the pope's future home: A four-story building attached to a monastery on the northern edge of the Vatican gardens where cloistered nuns used to live.