Pope Francis opened a synod on Sunday to champion the Amazon's poverty-stricken and isolated indigenous communities by condemning the destructive "interests" he blamed for the fires that devastated the region.

Representatives of the Amazon rainforest's ethnic groups attended the synod with Pope Francis Representatives of the Amazon rainforest's ethnic groups attended the synod with Pope Francis Photo: AFP / Tiziana FABI

The three-week synod, or assembly, is to unite 184 bishops, including 113 from the nine countries of the pan-Amazon region, including Brazil.

Brazil is home to 60 percent of the world's largest rainforest, which is vital for the planet but is suffering from its worst outbreak of fires in years.

There is growing alarm at the deforestation of the Amazon There is growing alarm at the deforestation of the Amazon Photo: AFP / Joao LAET

The fires, mostly caused by humans with the goal of clearing land for farming and cattle ranching, are having a grievous effect on the forest.

Representatives of indigenious peoples, some with their heads adorned with coloured feathers, also gathered in Saint Peter's Square to hear the pope's inaugural mass.

Aerial picture showing a fire raging in the Amazon rainforest about 65 km from Porto Velho, in the state of Rondonia, in northern Brazil, on August 23, 2019 Aerial picture showing a fire raging in the Amazon rainforest about 65 km from Porto Velho, in the state of Rondonia, in northern Brazil, on August 23, 2019 Photo: AFP / Carl DE SOUZA

"The fire set by interests that destroy, like the fire that recently devastated Amazonia, is not the fire of the Gospel," the pontiff said in his homily.

"The fire of God is warmth that attracts and gathers into unity. It is fed by sharing, not by profits.

The run-up to the synod saw hundreds of events held in the Amazon region in a bid to give the local populations a voice in the assembly's working document The run-up to the synod saw hundreds of events held in the Amazon region in a bid to give the local populations a voice in the assembly's working document Photo: AFP / Tiziana FABI

"The fire that destroys, on the other hand, blazes up when people want to promote only their own ideas, form their own group, wipe out differences in the attempt to make everyone and everything uniform."

Map of the Amazon used by the synod charged with protecting the rainforest and its inhabitants Map of the Amazon used by the synod charged with protecting the rainforest and its inhabitants Photo: AFP / Patricio ARANA

'Predatory and ecocidal development'

The working document for the synod denounced in scathing terms social injustices and crimes, including murders, and suggested a Church action plan.

"Listen to the cry of 'Mother Earth', assaulted and seriously wounded by the economic model of predatory and ecocidal development... which kills and plunders, destroys and devastates, expels and discards," the 80-page document said.

The way of life of the Amazon's indigenous peoples in under threat The way of life of the Amazon's indigenous peoples in under threat Photo: AFP / Tiziana FABI

The run-up to the synod saw some 260 events held in the Amazon region involving 80,000 people, in a bid to give the local populations a voice in the document.

Among those attending the synod as an observer was Sister Laura Vincuna, a missionary trying to protect the territories of the Caripuna indigenous people in the Brazilian Amazon.

The pope warned against "the greed of new forms of colonialism The pope warned against "the greed of new forms of colonialism" Photo: AFP / Tiziana FABI

"Help us defend our motherland, we have no other home!" she said on Saturday.

"Earth, water, forest: without these three elements nobody can do anything".

Jose Luiz Cassupe, a member of an indigenous community from Brazil's Ronodia state, said the Brazilian government "did not keep its word".

"We are asking the world for help because we are very worried about the new mining exploration policy in the Amazon," he told AFP, wearing a headdress of indigo blue feathers.

'New forms of colonialism'

Sunday's gathering comes as Brazilian President Jair Bolsonaro, a climate-change sceptic, told the United Nations that the world's media were lying about the Amazon, and attacked indigenous leaders as tools of foreign governments.

In his 2015 encyclical on ecology and climate change "Laudato Si", Francis denounced the destruction of the Amazonian rainforest in the name of "enormous international economic interests".

Last year, the world's first Latin American pope visited Puerto Maldonado, a village in southeastern Peru surrounded by the Amazon jungle, to meet thousands of indigenous Peruvians, Brazilians and Bolivians.

That trip was the first step towards the synod which opened Sunday.

The pope in his homily also voiced regret that the Church had in the past promoted "colonisation rather than evangelisation", but warned against "the greed of new forms of colonialism".

Francis' hopes of bringing the Catholic faith to far-flung populations will also see the bishops gathered in Rome debate a highly controversial proposal -- allowing married men to become priests.

The issue deeply upsets some traditionalists, who argue that making an exception for the Amazon would open the door to the end of celibacy for priests, which is not a Church law and only dates back to the 11th century.

The German Catholic Church in particular, which has an influential progressive wing, has been hotly debating the subject.

The synod will also reflect on making official roles for women, who already play a central part in the Amazonian Church.