Pope Francis said on Sunday he would elevate five Roman Catholic prelates to the rank of cardinal, the elite group of churchmen who are his closest advisors and can enter an eventual conclave to choose his successor.

Naming new cardinals is one of the most significant powers of the papacy, allowing a pontiff to put his stamp on the future of the 1.2-billion-member Roman Catholic Church.

The pope made the surprise announcement during his weekly Sunday address. He said the men came from Mali, Spain, Sweden, Laos and El Salvador and the ceremony to elevate them, known as a consistory, would take place on June 28.

The new cardinals were named as Archbishop Jean Zerbo of Bamako, Mali, Archbishop Juan José Omella of Barcelona, Bishop Anders Arborelius of Stockholm, Sweden, Bishop Louis-Marie Ling Mangkhanekhoun of Pakse, Laos and Bishop Gregorio Rosa Chávez of Mulli, El Salvador.

Only cardinals aged under 80 can enter a secret conclave to choose a new pope from their own ranks after Francis dies or resigns. All the new cardinals are currently under that age threshold.

It will be Francis's fourth consistory since his election in 2013 as the first non-European pontiff in 1,300 years and he has used each occasion to show support for the Church in far flung places or where Catholics are suffering.