Russia's foreign ministry has said it will only consider opening up Ukraine's Black Sea ports - and so alleviate pressure on global food supplies - if sanctions against it are reviewed.
Moscow's comments followed an appeal by the United Nations food chief to Vladimir Putin that millions would die around the world because of the Russian blockade.
International authorities are warning of a global food shortage crisis caused by the war in Ukraine.
The country, along with Russia, is one of the largest cereal producers in the world. But Moscow's blockade of Black Sea ports means exports are stuck in port.
"You have to not only appeal to the Russian Federation but also look deeply at the whole complex of reasons that caused the current food crisis," the Interfax news agency reported Russian deputy foreign minister, Andrei Rudenko, as saying.
"In the first instance, these are the sanctions that have been imposed against Russia by the US and the EU that interfere with normal free trade, encompassing food products including wheat, fertilisers and others," he added.
Earlier, United Nations food chief David Beasley appealed directly to the Russian president.
"If you have any heart at all for the rest of the world, regardless of how you feel about Ukraine, you need to open up those ports," he said.
The United Nations is calling on Russia to ensure food supplies get to where they are most needed.
“There is no effective solution to the food crisis without reintegrating Ukraine’s food production, as well as the food and fertilizer produced by Russia and Belarus, into world markets -- despite the war,” said António Guterres, Secretary-General of the United Nations.
“Russia must permit the safe and secure export of grain stored in Ukrainian
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