POPE LEO, IN CAMEROON, DECRIES 'HANDFUL OF TYRANTS' RAVAGING THE WORLD. (PHOTO).

 Pope Leo, in Cameroon, decries 'handful of tyrants' ravaging the world

Pope Leo blasted leaders who spend billions on wars and said the world was "being ravaged by a handful of tyrants", in unusually forceful remarks in ‌Cameroon on Thursday days after U.S. President Donald Trump attacked him on social media.

Leo, the first U.S. pope, also decried leaders who used religious language to justify wars and urged a "decisive change of course" in a meeting in the biggest city in Cameroon's anglophone regions, where a simmering conflict going back nearly a decade has left thousands dead.

"The masters of war pretend not to know that it takes only a moment to destroy, yet often a lifetime is not enough to ​rebuild," the pontiff said, Reuters reported.

"They turn a blind eye to the fact that billions of dollars are spent on killing and devastation, yet the resources needed for healing, education and restoration ​are nowhere to be found."

'A WORLD TURNED UPSIDE DOWN'

Trump's attacks on Leo, first launched on the eve of the pope's ambitious four-country tour of Africa ⁠and repeated late Tuesday, have caused dismay in Africa, where more than a fifth of the world's Catholics live.

Speaking in the anglophone city of Bamenda, the pontiff also sharply criticised leaders who invoked religious themes to justify wars.

"Woe to those who manipulate religion and the very name of God for their own military, economic and political gain, dragging that which is sacred into darkness and filth," he said.

"It is a world turned upside down, an exploitation of God’s creation that must be denounced and rejected by ​every honest conscience."

THREE-DAY CEASEFIRE DURING VISIT

After arriving in the Cameroon capital Yaounde on Wednesday, Leo urged the government of the Central African nation - led by President Paul Biya, at 93 the world's oldest ruler - to root out corruption and resist "the whims of the rich and powerful".

During a Mass at the airport in Bamenda on Thursday, attended by around ​20,000 people, the pope criticised foreigners who exploited ​Africa's wealth, saying they were contributing to ⁠widespread poverty and underdevelopment.

"The time has come, today and not tomorrow, now and not in the future, to restore the mosaic of unity by bringing together the diversity and riches of the country and the continent," he said.

Leo's trip on Thursday to Bamenda has stirred faint hope that steps might be taken ​to resolve the conflict there, rooted in the country's complex colonial and post-colonial history.

More than 6,500 people have been killed and more than half a million displaced in fighting between government forces and anglophone separatist groups, according to the International Crisis Group.