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 ports.
“And Russian food and fertilizers must have unrestricted access to world markets without indirect impediments.”
Before the war, food insecurity had increased due to conflicts, climatic and economic crises.
The World Bank has announced $12 billion (€11.3 billion) in aid over the next fifteen months, the majority of which will go to countries in Africa, the Middle East, and Eastern Europe.
“This is a crisis that is poised to get worse compared to the food price crisis in 2007 to 2008, affecting many, many poor households,” said Martien Nieuwkoop, Agriculture and Food Global Director of the World Bank.
“We see already food insecurity at very high levels. The support will be used to protect poor households by scaling up social safety nets.
“It will help farmers to get ready for the next planting season. It will also be used to make sure that export restrictions are avoided. And that food and food trade stays open, to avoid price increases."
The United States has also underlined its commitment to fight against famine and malnutrition.
In just two years, the number of people suffering from severe food insecurity has doubled, from 135 million before the COVID-19 pandemic to 276 million, according to the UN.
It added that last year, 193 million people in 53 countries were in a situation of acute food insecurity.
"In total, this represents more than $30 billion (€28.3 billion) available for the implementation of the fight against food insecurity over the next 15 months," noted the World Bank.
"Rising food prices are having devastating effects on the poorest and most vulnerable," said World Bank President David Malpass.
"To inform and stabilise markets, it is essential that countries make clear statements now on future production increases in response to Russia's invasion of Ukraine.”