VATICAN CITY (AP) — Catholic cardinals will sequester themselves Wednesday behind the Vatican’s medieval walls for the start of a conclave to elect the 267th pontiff of the Roman Catholic Church, a successor to Pope Francis who died in April at the age of 88.

The 133 cardinals from 70 countries will be locked inside the Sistine Chapel, where they will vote in secret and silence, a process designed to be both contemplative and free from outside interference. They will surrender their cellphones and airwaves around the Vatican will be jammed to prevent them from all communications until they find a new leader for the 1.4 billion-member church.

Here is the latest:

Rome on high alert ahead of the conclave

The Vatican’s Swiss Guards and Italian carabinieri and police have been mobilized as Rome and the wider world hold their breath to see who will emerge from the conclave as the next pontiff.

As of Wednesday morning, when cardinals attended a special pre-conclave Mass in St. Peter’s Basilica, police were carrying out enhanced checks of people entering St. Peter’s Square.

Over 4,000 officers have been deployed, with an anti-drone system and signal jammers to block communication between the cardinals and the outside world once they enter into their secret assembly.

“The safety of the cardinals is a priority, but so is that of the faithful outside,” said Fabio Ciciliano, head Italy’s Civil Protection agency.

A please to choose a pope who prizes unity in diversity

A senior cardinal has urged the cardinals who will vote in the conclave to elect a pope who prizes unity in diversity, and puts personal interests aside.

Cardinal Giovanni Battista Re, the dean of the College of Cardinals, outlined the marching orders for the 133 men who will enter the Sistine Chapel later on Wednesday to begin voting to elect a new pope.

In his sermon at the final pre-conclave Mass at St. Peter's Basilica, Re reminded the cardinals that a conclave represented the highest human and church responsibility, and that they must set aside “every personal consideration.”

He said the new pope should foster communion and unity within the church.

A final pre-conclave Mass

Cardinals have entered St. Peter’s Basilica on Wednesday to celebrate the final Mass before the conclave to elect a new pope.

The dean of the College of Cardinals, Giovanni Battista Re, is celebrating the Mass and leading the prayers for cardinals to find the wisdom, counsel and understanding to choose a worthy new shepherd.

Re, 91, had presided at Francis’ funeral two weeks ago, delivering a heartfelt sermon recalling history’s first Latin American pope and the reforming 12-year papacy he oversaw.

Later in the day, the cardinals will sequester themselves in the Sistine Chapel to begin casting their ballots.

How the voting works

The electors cast paper ballots, and voting continues until one candidate receives a two-thirds majority, or 89 votes. After two rounds of voting, ballots are burned in a special stove — black smoke signals no decision, while white smoke means a new pope has been chosen.

The last few popes have been elected within a few days, but there is no formal deadline. Electors must be under 80, and are more geographically diverse than ever.

They represent Catholicism’s growing presence in Africa, Asia and Latin America, as well as its traditional power base in Europe.

Prayers in the Philippines for another pope good for poor people

Nearly 100 people in a slum in Manila, the Philippine capital, were praying Wednesday for the conclave to elect another pope who will reach out to the poor.

Rev. Robert Reyes told the crowd in a small chapel surrounded by shanties in suburban Quezon city that the next pope should be humble and inclusive, like Francis.

“Francis was such a unique person open to all, specially to those who are neglected, forgotten, marginalized, rejected and oppressed,” said Reyes.

The Philippines, the largest Roman Catholic nation in Asia, has long been plagued by poverty and inequality.