"It is our profound conviction that exploiting these resources can contribute to improving our population's conditions of life," the bishops' commission for natural resources said in a statement in late September.

The commission said "awareness by the major polluting countries comes nowhere near to any concrete commitment, or to the efforts required in countries whose forests provide the lungs for conserving the world's bio-diversity."

The statement, issued Sept. 25 in Kinshasa, said experts on mining, hydrocarbons, forestry and environmental protection had all stressed an urgent need to combat the "illegal, clandestine, irrational and irresponsible exploitation" of Congo region's resources.

"The fact is that these resources are being exploited without responsibility, and that this now constitutes an increasingly serious menace to our common home, environment and planet," the commission said.

Western firms have been accused of working with violent groups in the DRC and other countries to obtain minerals used for producing mobile phones, laptops and other consumer objects. They also have been accused of allowing trade in resources to perpetuate human rights violations.

In 2012, the Dodd-Frank act required companies listed on American stock markets to "undertake supply chain due diligence" by checking whether minerals in their products helped fund armed groups, while a European Union directive in 2013 also stipulated payment transparency in extractive industries.

However, in February, 130 Catholic bishops from 37 countries said many European firms remained "complicit in abuses" through their supply chains, while most of the EU's 28 member-countries imported significant amounts of resources from conflict-affected regions.The Congolese commission said resources were being illegally extracted from the country's Virunga and Salonga national parks, as well as from animal reserves and other areas "with contempt for vital needs of local populations."

It added that indigenous inhabitants had been uprooted from the country's Equateur, Katanga and Maniema provinces "without just compensation," in defiance of laws, regulations and social agreements, while forests and land resources had been exploited by multinational businesses "anarchically without any framework."

"The deep motivation for our work rests on the dignity of mankind created in the image and likeness of God," said the commission, which works with the U.S. bishops' Catholic Relief Services and other aid agencies.

"Pope Francis is encouraging civil society organizations to use legitimate mechanisms of pressure to ensure each government accomplishes its proper and untransferrable duty of preserving the environment and natural resources, without selling out to illegitimate local or international interests."

In a March statement, the Brussels-based CIDSE, grouping 17 Western Catholic charities, said the country had suffered "mutilation, massacres, rape, slavery and massive displacement" during 15 years of war, at the hands of armed groups financed by "riches of the subsoil."

Up to 5.4 million people were killed in Congo in a series of 1995-2003 wars involving nine countries and two dozen armed groups, while militia violence has since continued in many parts of the mineral-rich country.

Henri Muhiya, commission spokesman, said the government had not reacted officially to the latest appeal, but added that local Catholics and Congolese media had noted "the Catholic Church is speaking out, mobilizing and intervening."

"The church's voice counts a great deal here -- and in certain ruling circles it's very much needed," Muhiya told Catholic News Service Sept. 30.

"At the start of a new Holy Year, when bishops in the U.S. and Europe are also involving themselves in key social questions, we need to see how the destruction of natural resources is closely linked with the violation of human rights and fundamental values."