TEMUCO, Chile -- Pope Francis denounced the use of violence to achieve political gains as he travelled Wednesday to the heart of Chile's centuries-old conflict with indigenous peoples, where several church burnings have been blamed on radical Mapuche factions pressing for their cause.

Hours after two more churches and three helicopters were torched, Francis celebrated Mass at a former military base that not only lies on contested indigenous Mapuche land but was also a former detention centre used during Chile's brutal dictatorship.

Leading some 150,000 people in a moment of silent prayer, Francis said the fertile green fields and snow-capped mountains of the Mapuche heartland in Chile's southern Araucania region were both blessed by God and cursed by man, the site of "grave human rights violations" during the 1973-1990 dictatorship.

"We offer this Mass for all those who suffered and died, and for those who daily bear the burden of those many injustices," he said.

Francis also referred to the more recent violence that has flared in Araucania, Chile's poorest region. No one has claimed responsibility for the 11 firebombs that have damaged, or in some cases, burned churches to the ground in recent days, or the three helicopters that were torched overnight.

Prosecutor Enrique Vasquez told local media Wednesday that investigators found a sign and pamphlets demanding the release of Mapuche prisoners at the scene of the burned church, while pro-Mapuche pamphlets were found at the scene of the burned helicopters.

The Argentine Jesuit pope took radical factions to task, saying violence wasn't the answer to their grievances.

"You cannot assert yourselves by destroying others, because this only leads to more violence and division," he admonished in his homily. "Violence begets violence, destruction increases fragmentation and separation. Violence eventually makes a most just cause into a lie."

At the same time, he demanded the government not just negotiate "elegant" agreements with the indigenous, but actually implement them.

The Argentine pope is particularly attuned to indigenous issues and their campaigns for recognition of their land, culture and traditions. He hopes to use his weeklong trip to Chile and Peru to put the issue on the global agenda and set the stage for a big church meeting next year on the Amazon and native peoples who live there.

In that sense, the Maquehue Air Base was a symbolically poignant site for his Mass dedicated to the region's indigenous people, built on land taken from the Mapuche in the early 20th century. And the Mass was full of Mapuche culture and symbolism, with traditional music and prayers sprinkled throughout.

But the site of the Mass also had a more recent, bloody past: The base was used as a detention centre during the dictatorship of Gen. Augusto Pinochet, during which around 40,000 people were killed, tortured or imprisoned for political reasons. The government estimates that 3,095 were killed, including about 1,200 who were forcibly disappeared.

History's first Latin American pope knows well the history of the time, since he was a young Jesuit superior during neighbouring Argentina's "Dirty War," during which thousands of suspected leftists were killed, imprisoned or disappeared at the hands of the military junta.

Francis' gesture of celebrating Mass on the specific site of the atrocities recalled St. John Paul II's famous 1987 visit to Chile during the waning years of the Pinochet regime. In one of the most poignant moments of that trip, the Polish pope delivered a speech to young people gathered in Santiago's national stadium, which had been used as a detention and torture centre.

With the wounds of the regime still alive, John Paul urged Chile's youth to look forward with hope, even from a place of "pain and suffering."

Francis repeated those same words Wednesday in his Mass, which began with Mapuche natives performing a traditional horn and drum ceremony at the altar as Francis and other priests looked on.

After the service, Francis had lunch with eight Mapuche in a religious retreat house, breaking bread over an enormous lunch of mushroom ragout, octopus carpaccio, crab claws, osso buco with saffron rice and vegetables, and flan. They were joined by a woman the Vatican described as a "victim of rural violence" as well as a descendant of the German-Swiss colonizers who clashed for centuries with the Mapuche.

Francis had raised the plight of the indigenous in his first speech on Tuesday to government authorities, urging Chileans to listen to indigenous peoples who are "often forgotten, whose rights and culture need to be protected lest that part of this nation's identity and richness be lost."

Those initial statements were already reverberating among many in the Mapuche community when Francis celebrated the Mass on Wednesday.

"The recognition (of the Mapuche people) has to come from the state and not from the church," said Daniel Antiman, a Mapuche representative who performed in front of the Pope during the Mass.

How likely that is remains to be seen, as the conflict is one of Latin America's longest involving indigenous peoples.

Leaders of both the Mapuche and the Chilean government have expressed hope that Francis can facilitate dialogue. Their disputes date back to the late 19th century, when the Chilean military finally defeated the Mapuche, who had ferociously resisted Spanish and other European settlers for centuries.

Mapuche groups are pushing for ownership of ancestral lands, legal recognition of their language and culture, and a stop to discrimination that leaders say often makes them police targets.

While the vast majority of Chile's estimated 1 million citizens of Mapuche descent oppose using violence, a small number rely on it to push their agenda.

In recent years dozens of churches have been among the targets. Outside one of the churches attacked last week, pamphlets extolling the Mapuche cause were found.

Some 4,000 police officers were deployed in Temuco, the capital of the Araucania region, as protests were expected.

In recent decades, the Mapuche community has made significant strides. Some ancestral lands have been returned, though the program is controversial. University scholarships have been set aside for Mapuche young people and various aspects of Mapuche culture, such as many foods, have become part of the mainstream.

Still, myriad problems persist and many Mapuche complain of frequent discrimination.

Albertina Urrutia Valencia, a Mapuche activist, says the Mapuche cause is still largely invisible.

"What do you see? The burning of trucks, Mapuches in jail," she said. "What you don't see is what is behind all that."

"If people are repressed for hundreds and hundreds of years, it's obvious they are going to fight back," she added.

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Associated Press writer Peter Prengaman in Santiago and AP video journalist Mauricio Cuevas contributed to this report.