A report from the agency's Food and Agriculture Organization on Friday shows the far-reaching fallout of the war on the world's food system, with the impact set to stretch well beyond the next season. Ukraine and Russia together account for more than a tenth of all calories traded globally, and those flows have been stifled since the conflict erupted late last month.

Soaring production costs means other countries will only partly be able to compensate for the "sudden and steep reduction" in Black Sea grain and sunflower exports in the coming 2022-23 season, FAO said. That will likely push international food and feed prices 22% higher and a "considerable" supply gap will linger going forward if the war persists and energy stays expensive.

"The likely disruptions to agricultural activities of these two major exporters of staple commodities could seriously escalate food insecurity globally," Qu Dongyu, FAO director general, said in a separate statement, adding hunger could also rise in Ukraine. "International food and input prices are already high and volatile."

Read more: The world's next food emergency is here as war componds hunger.