Pope Francis demanded an immediate end Thursday to what he called 'a genocide' of Christians taking place in the Middle East and beyond, describing it as a third world war.

Bolivia: Pope Francis demanded an immediate end on Thursday to what he called "a genocide" of Christians taking place in the Middle East and beyond, describing it as a third world war.

The pope, who has never been afraid to weigh into delicate issues both religious and political, made the comments in Bolivia, the second stop on a three-nation tour to his home continent of South America.

"Today we are dismayed to see how in the Middle East and elsewhere in the world many of our brothers and sisters are persecuted, tortured and killed for their faith in Jesus," Pope Francis said.

"In this third world war, waged piecemeal, which we are now experiencing, a form of genocide is taking place, and it must end."

In September last year he lamented a rash of global conflicts, saying they were effectively a "piecemeal" third world war and condemning "terrorism."

He has also in the past voiced grave concern about the dangers facing Christians around the world, including in Iraq and Syria, where the Islamic State extremist group has overrun large areas in a brutal offensive of beheadings and forced conversions.

His latest remarks, at a so-called World Meeting of the Popular Movements in the city of Santa Cruz, came after he apologized for "offenses" committed by the Catholic Church against indigenous peoples during the colonial-era conquest of the Americas.

The first Latin American pope "humbly" begged forgiveness, during an encounter that included indigenous groups and other activists.

"I say this to you with regret," he told an enchanted crowd. "Many grave sins were committed against the native peoples of America in the name of God."

One million

Earlier in the day, Pope Francis, a champion of the poor and social justice, called on a million faithful to reject today's consumer society, at an open-air mass.

The pope addressed the throng in the vast Christ the Redeemer Plaza in Santa Cruz, including many people who camped out overnight to see him.

He denounced what he called a "mentality in which everything has a price, everything can be bought, everything is negotiable. This way of thinking has room only for a select few."

"Jesus speaks these words to us, here in this square. No one has to be discarded," the 78-year-old pontiff told the crowd, estimated by authorities in Bolivia -- South America's poorest nation -- at one million strong.

The two-hour service featured religious hymns and chants. Hundreds of musicians also played Baroque works, introduced by Spanish Jesuit missionaries in the 18th century and still very popular in this country.

Thousands in the crowd were from Bolivia's indigenous majority and President Evo Morales, the country's first indigenous leader, was in the front row.

Around the plaza, dominated by the giant bronze Christ the Redeemer statue, big-screen TVs were erected for people to watch the religious service.

'As close as possible'

Since his election in 2013, Francis -- who hails from Argentina and is also the first Jesuit pope -- has indeed shown himself to have a down-to-earth air about him, and that is ringing clear in Santa Cruz.

He and several bishops are reportedly using a Burger King restaurant as their sacristy -- the place where they don their vestments and make other preparations for mass.

"We want to be as close as possible to receive the blessings that he is going to bestow," said one of the campers who waited overnight to see the pope, Nancy Camacho, her head wrapped in a thick scarf.

Francis arrived in Bolivia on Wednesday evening in the high-altitude Andean city of La Paz -- more than 4,000 meters (13,000 feet) above sea level.

Concerned authorities had extra oxygen tanks on hand for the pope, who lost a lung during his youth, but he was not seen using it.

He will head on Friday to Paraguay, the last stop on his tour of South America, which began in Ecuador.

A robust pontiff

Francis has impressed people with his stamina as he walked amid crowds, kissed people and took selfies. Some of the journalists traveling with him had to stop and take a shot of oxygen.

Bolivia is destitute -- the minimum monthly wage is equivalent to about $240 a month -- but has made economic progress in recent years.

Alcohol sales and musical performances have been banned throughout Bolivia during the pope's visit, and 17,000 police and soldiers have been deployed.

All three of the countries Francis is visiting are predominantly Catholic and have been marked by a long history of poverty and inequality mostly afflicting indigenous populations.