To add details and quotes

By Joshua McElwee

LUANDA, April 18 (Reuters) - Pope Leo XVI strongly condemned the exploitation of natural resources in Africa on Saturday, criticizing "tyrants and despots" who promise riches but fail to deliver, leading to suffering and death.

In a speech in oil-rich Angola, the third stop on his four-nation African tour, Leo called on Angolan citizens to work for a society free from "the slavery imposed by the affluent elite who enjoy enormous wealth but live in false bliss."

Léo adopted a distinctly new tone in his rhetoric during the tour, which began last week amid criticism from US President Donald Trump. During his trip from Cameroon to Angola, he sought to downplay the rift between them, telling reporters that his earlier remarks about "dictators" were not directed at Trump and that he was not interested in engaging in a dispute with him.

Upon his arrival in Luanda, the capital of Angola, Pope Leo expressed his regret that "powerful entities are monopolizing" the natural resources of the former Portuguese colony, in a clear reference to foreign companies that are profiting from Angola's oil and diamond sectors and its emerging strategic minerals sector.

In his address to Angolan President Joao Lourenço and several political leaders, the Pope said, "People have always been interested, and still are, in your lands... with the aim of seizing them."

He added, "How much suffering, how many deaths, and how many social and environmental disasters result from this extraction logic!"

* The Pope's candor in Africa

Leo, who was born in Chicago, USA, maintained a relatively reserved stance towards the Pope during the first ten months of his tenure, but he has shown a new and clear style of speaking about a range of issues.

In strongly worded remarks, the Pope condemned wars and inequality during his 10-day African tour, one of the most complex trips organized for a Pope in decades, as he is scheduled to travel nearly 18,000 kilometers via 18 flights to 11 cities and towns in four countries.

Although Angola is a leading oil producer in sub-Saharan Africa, its 36.6 million inhabitants suffer from extreme poverty, with the World Bank saying that more than 30 percent of the population lives on less than $2.15 a day.

More than half of the country's population belongs to the Catholic Church.

Leo called on the Angolan people to "break this cycle of interests, which reduces reality, and even life itself, to mere commodities."

He urged the country's political leaders to focus on helping all their people, not just corporate interests.

He said, "History will do you justice then, even if some oppose you in the near future."

200,000 people attended the Pope's mass in Cameroon

Before traveling to Angola earlier today, Leo held a mass before leaving the Cameroonian capital, Yaoundé, urging those present not to lose hope despite the challenges facing the Central African nation, including an ongoing conflict that has claimed thousands of lives.

Speaking to a crowd estimated by the Vatican at around 200,000 people, making this Mass the biggest event of his tour so far, the Pope said, "When we feel that we are sinking and being crushed under the weight of hostile forces, and when everything seems dark... Jesus Christ is with us. And this is a power stronger than all the forces of evil."

The crowds that welcomed the Pope in Cameroon showed great enthusiasm for his visit, including an estimated 120,000 who attended Mass on Friday in Douala. Thousands more lined the streets along his motorcade route, many wearing colorful costumes bearing his image.