By Philip Pullella
VATICAN CITY (Reuters) - Pope Francis on Saturday inducted new Roman Catholic cardinals to the group that will choose his successor, telling them their high rank was a call to be humble and work for justice.
Francis elevated 20 prelates, many of them from developing countries, at a ceremony in St. Peter's Basilica. It was attended by former Pope Benedict XVI, making only his fifth public appearance at a church event since his resignation in 2013.
In his homily, Francis said being a cardinal "is not a kind of accessory, a decoration, like an honorary title". He warned against being "puffed up with pride", adding: "Nor are church dignitaries immune from this temptation."
Cardinals are the pope's highest ranking aides in Rome and around the world. Those under 80 can enter a secret conclave to elect the next pontiff after Francis's death or resignation.
Since his election, Francis has often criticized careerism and privileges among the clergy, setting an example by living in a Vatican guest house instead of the large papal apartments used by his predecessors.
Fifteen of those who received their red "biretta" hats on Saturday are under 80, bringing the total number of "cardinal electors" to 125. The five older men were honored for their long service to the church.
The new electors, whose names were announced last month, are from Italy, France, Portugal, Ethiopia, New Zealand, Vietnam, Mexico, Myanmar, Thailand, Uruguay, Spain, Panama, Cape Verde and Tonga. Nine are from the developing world.
It is the first time cardinals from Myanmar, Tonga or Cape Verde have been appointed.
Cardinal Alberto Suarez Inda of Morelia, Mexico, has worked in a region hit by violence related to drug cartels. Cardinal Francesco Montenegro of Sicily has been in the front line in efforts to help migrants making the dangerous crossing from north Africa to the island of Lampedusa. Thousands have died.
"Those called to the service of governance in the church need to have a strong sense of justice, so that any form of injustice becomes unacceptable," said Francis.
(Reporting by Philip Pullella; editing by Andrew Roche)