Pope Leo on Sunday described those who wage wars and appropriate the earth's resources as thieves who ​rob the world of a peaceful future, issuing ‌a warning about the use of nuclear power on the anniversary of the Chornobyl reactor accident.

Ukraine is commemorating the 40th anniversary of the world's ​worst nuclear disaster on Sunday amid lingering fears ​that Russia's four-year-old war could spark a repeat of ⁠the tragedy

In his weekly address after the Angelus prayer, ​the Pontiff said the Chornobyl accident had left a mark ​on humankind's collective conscience.

"It remains a warning over the use of ever more powerful technologies," the Pope, who has just returned from a 10-day tour ​across four African nations, said.

"I hope that at all decision-making ​levels, wisdom and responsibility always prevail, so that atomic power can always ‌be ⁠used to support life and peace," he added.

Commenting on the Gospel of the day, which contained the metaphor of a sheep thief, Pope Leo said thieves came under many ​appearances, listing as ​examples "superficial lifestyles ⁠driven by consumerism", prejudices and wrong ideas.

"And let's not forget also those thieves who, by ​plundering the earth's resources, by fighting bloody wars ​or ⁠feeding evil in whichever form, are simply taking away from all of us the chance of a future of peace and ⁠serenity," ​he added.

Leo, the first U.S. pontiff, ​has attracted the ire of President Donald Trump after becoming more outspoken against ​war and despotism.