RIO DE JANEIRO (AFP) - Pope Francis has pledged to donate US$5 million (S$6.2 million) to help pay off part of the debt accrued organizing the 2013 World Youth Day in Rio de Janeiro last July, the Brazilian city's archdiocese said.

"Aware" of the issue, the pope "indicated his intention to contribute financial aid to pay part of the expenses" of the major event, which he presided over soon after he was elected head of the world's 1.2 billion Roman Catholics, the archdiocese said on its website Friday.

The first Latin American pontiff pledged 11.7 million reais (S$6.2 million), to help pay off the 43.2 million reais still owed by the organization that put on the youth event.

The days-long festival, which closed with a papal mass attended by some three million faithful on Rio's famous Copacabana beach, was funded entirely by the Church and donations - without contributions from Brazil's government.

"The participation of the public administration was limited to ensure the operation of public services during the event," the archdiocese explained.

The debt, which started out at 91.3 million reais, has already been partly paid down by the sale of one of the archdiocese's buildings, as well as by donation campaigns and the sale of DVDs and CDs from the event.