India on Saturday (May 14) banned wheat exports without prior government approval after recent scorching temperatures hit production, in a blow to countries affected by supply shortages because of the war in Ukraine.
India, the world's second-largest wheat producer, said that factors including lower wheat production and sharply higher global prices because of the war meant that it was now worried about its own "food security".
All export deals agreed before the directive issued on Friday could still be honoured, but all future shipments needed to have government approval.
However, exports could also take place if New Delhi approved a request by other governments "to meet their food security needs."
Agriculture ministers from the Group of Seven industrialised nations on Saturday condemned India's decision to ban unapproved wheat exports after the country was hit by a punishing heatwave.
"If everyone starts to impose export restrictions or to close markets, that would worsen the crisis," German agriculture minister Cem Ozdemir said at a press conference in Stuttgart.
Some "20 million tonnes" of wheat were sitting in Ukrainian silos and "urgently" needed to be exported, Ozdemir said.
Before the invasion, Ukraine exported 4.5 million tonnes of agricultural produce per month through its ports -- 12 percent of the planet's wheat, 15 percent of its corn and half of its sunflower oil.
They "spoke out against export stops and call as well for markets to be kept open", said Ozdemir, whose country holds the rotating presidency of the group.
"We call on India to assume its responsibility as a G20 member," Ozdemir added.