Cardinal Baldassare Reina, General Vicary for the diocese of Rome, said on Monday (April 28) that this is 'no time for tactics' as he presided over a mass to mourn Pope Francis.

Roman Catholic cardinals will begin their secret conclave to elect the new leader of the global Church on May 7, the Vatican said on Monday, confirming what a source had previously told Reuters.

Who, what, why and when: An expert's view on the conclave

What we know ahead of the conclave

The date was decided during a closed-door meeting of cardinals at the Vatican, the first since the funeral of Pope Francis on Saturday (April 26).

Some 135 cardinals, all under the age of 80 and from all corners of the world, are eligible to take part in the vote for the next head of the 1.4-billion-member Church, which is beset by concerns over its finances and divisions over doctrine.

The previous two conclaves, held in 2005 and 2013, lasted just two days. But Swedish cardinal Anders Arborelius said on Monday that the coming ballot may take longer, as many of the cardinals appointed by Pope Francis have never met each other.

Francis made a priority of appointing the red-hatted "Princes of the Church" from countries that had never had them, such as Myanmar, Haiti, Rwanda and Arborelius' own Sweden.