European Council President Charles Michel said Friday that Russia "must stop" its blockade of Ukrainian seaports after pulling out of a United Nations and Turkey-mediated deal to ensure grain shipments.

Michel told reporters in India's capital New Delhi ahead of a G20 summit; "It's frankly scandalous that Russia, after having terminated the Black Sea grain initiative, is blocking and attacking Ukrainian ports. This must stop,"

Russia pulled out of the grain agreement in July after claiming that it had failed to fulfil the goal of relieving hunger in Africa, as tension was built up in the region with Russia mounting attacks on Ukrainian export hubs and Kyiv's forces targeting Moscow's naval ports and warships.

The Kremlin has since asked Turkey to help Russia export its grain to African countries without any involvement from Ukraine, as President Vladimir Putin said Monday that Moscow is just weeks away from supplying free grain to six African countries.

"The Kremlin's offer of one million tonnes of grain to Africa is absolutely cynical," Michel said.

"Ships with grains need to have safe access to the Black Sea," he said, noting that the UN initiative had initially delivered 32 million tonnes to the market, "especially to developing countries".

He noted that last year's grain agreement helped push down global food prices and provided Ukraine with an important source of revenue to fight the war.

"Over 250 million people face acute food insecurity worldwide, and by deliberately attacking Ukraine's seaports, the Kremlin is depriving them of the food they desperately need," Michel added.