Christian Aid has welcomed the extension of a deal which will ensure grain can continue to be exported from the Black Sea port of Odesa.
Negotiators from Kyiv and Moscow have agreed to prolong a United Nations and Turkish-brokered export agreement for another 120 days. The deal was initially agreed in July to end Russia's blockade of Ukraine's ports.
Ukraine is the world's fifth-biggest exporter of wheat and in the top three for maize, barley and sunflower seeds.
The deal means food staples can continue to reach African and Mediterranean countries and help take the pressure off future prices.
Christian Aid says the renewal of the agreement is vital to the world's poorest people. The charity says higher food prices are bringing communities and countries to the brink of famine. East Africa is the hardest hit where hunger is being fuelled by one of the worst droughts in 40 years.
Elizabeth Hallinan, Global Contexts Crisis Lead, said:
"This news is a lifeline for poor countries struggling with high food prices. But with starvation stalking East Africa, it's critical the UK and other countries work to tackle hunger at its roots.
"The new extension is shorter than the original year-long agreement and does not provide the certainty needed. A sustainable long-term approach is required that allows free access to the world's most essentials foods."
Ukraine is believed to have exported more than 11million tonnes of agricultural products to 38 countries around the world since exports resumed in August.