Pope Francis on Wednesday called for "concrete steps" to end the war in Ukraine and avert the risk of a nuclear disaster at the Zaporizhzhia power plant.

IAEA, the U.N. nuclear watchdog, said on Tuesday it will visit the Russian-occupied plant in Ukraine within days if talks to gain access succeed.

Russia and Ukraine have repeatedly accused each other of firing at the facility, the largest of its kind in Europe and which pro-Moscow forces took over soon after the Feb. 24 invasion. The United Nations has called for the area to be demilitarised.

"I hope that concrete steps will be taken to bring an end to the war and to avert the risk of a nuclear disaster at Zaporizhzhia," Francis said at his weekly general audience.

Speaking on the day Ukraine marks its independence from Soviet rule in 1991 and six months after Russian forces invaded, Francis condemned wars as "madness" and referred to the death of Darya Dugina, daughter of a prominent Russian ultra-nationalist, in a car bombing near Moscow on Saturday.

"Innocents pay for war," he said.

Moscow blamed the killing on Ukrainian agents, a charge Kyiv denies.

Francis called arms merchants who profit from war "delinquents who kill humanity".

In an interview with Reuters last month, Francis said he wanted to visit Kyiv but also wanted to go to Moscow, preferably first, to promote peace.

Francis will attend a congress of religious leaders in the Kazakh capital Nur-Sultan on Sept. 13-15, where he has said he hoped to meet with Russian Orthodox Patriarch Kirill, who supports the war in Ukraine.

Ukraine has been lobbying Francis to go to Kyiv first, saying meeting Kirill before could send the wrong message to the Ukrainian people.