Moscow could allow food ships to leave Ukrainian ports on The Black Sea in exchange for the lifting of some sanctions imposed on Russia due to its invasion of Ukraine, said the Deputy Foreign Minister Andrei Rudenko.

Ukrainian ports have been blocked since Russia launched its war against Ukraine on February 24, leaving more than 20 million tonnes of grain stuck in silos in the country.

Russia and Ukraine make up almost a third of the world's wheat reserves. Ukraine is also a major exporter of corn and sunflower, and the blockade of its ports is contributing to the growing global food crisis.

"We have repeatedly stated that a solution to this food problem requires a comprehensive approach, including the lifting of sanctions on Russian exports and financial transactions," Rudenko was quoted as saying by Interfax.

Russia is in contact with the United Nations on this issue, Rudenko said, reports another news agency, RIA.

However, Rudenko, according to Interfax, warned that any possible escort from Western ships to Ukrainian ships carrying grain "would seriously worsen the situation in the Black Sea."

Rudenko denied reports in the Western media that Russian forces were stealing grain from Ukrainian ports.

"We completely reject this. "We are not stealing anything from anyone," he told reporters.

CNN previously published satellite images that allegedly confirmed that Russia was exporting grain from Ukraine via Crimea, a Ukrainian peninsula that Moscow illegally annexed in 2014.