Conclave to elect new pope starts on May 7, Vatican says

+ Last two conclaves took just two days to complete

+ Pope Francis' burial on Saturday drew huge crowds

+ Some cardinals want Francis' reforms to continue apace

+ Traditionalists seek a change of course

Vatican City - 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.

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

Some 135 cardinals, all under the age of 80 and from across the world, are eligible to take part in the conclave and decide who should be the next leader of the 1.4-billion-member Church.

The 16th-century Sistine Chapel, where conclaves are held, was closed to tourists on Monday to allow for preparations.

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

Francis made a priority of appointing cardinals from places that had never had them, such as Myanmar, Haiti and Rwanda.

"We don't know each other," said Arborelius, one of about 135 cardinals under the age of 80 who will enter the conclave.

The earliest the conclave could have begun was May 6, the Vatican said. Starting it a day later means cardinals will have slightly more time for their general discussions ahead of the momentous ballot.

The average length of the past 10 conclaves is three days.

Francis, pope since 2013, died aged 88 on April 21. His funeral on Saturday and a procession through Rome to his burial place at the Basilica of St. Mary Major attracted crowds estimated at more than 400,000.

German cardinal Walter Kasper told La Repubblica newspaper that the outpouring of mourners for Francis indicated that Catholics wanted the next pope to continue with his reforming style of papacy.

Francis, the first pope from Latin America, tried to open up the often staid Church to some new conversations. He allowed debate on issues such as ordaining women as clergy and outreach to LGBTQ Catholics.

"The People of God voted with their feet," said Kasper, who is 92 and will not take part in the conclave. "I am convinced that we must go ahead in the footsteps of Francis."

However, a bloc of conservative cardinals are certain to push back against this and seek a pope who reasserts traditions and reins in Francis' vision of a more inclusive Church.

(Editing by Crispian Balmer, Janet Lawrence and Kevin Liffey)