New York, Sept. 24 -- Ukrainian President Volodymyr Zelenskyy delivered a sharply worded warning at the UN General Assembly on Wednesday, accusing Russia of paying a staggering human cost for limited territorial gains and saying Moscow had "messed up" its war in Ukraine, while stressing that diplomacy backed by strength was the only path to ending the conflict.

He said Russia had suffered great losses between January and August, according to Ukrainian figures, "Russia messed up," Zelenskyy said, noting that Russia itself has around 17 million square kilometres of territory.

Zelenskyy revealed that between January and August this year alone, Russia lost nearly 249,000 soldiers killed or badly wounded, a number he said exceeds the entire po...