Russian-flagged ships are carrying grain harvested in Ukraine and transporting it to Syria, according to US satellite imagery company Maxar.
Satellite images show two Russian-flagged bulk carrier ships docked in the Russian-controlled Crimean port of Sevastopol in May and being loaded with grain, the company said on Thursday.
Days later, Maxar satellites collected images of the same ships docked in Syria, with their hatches open and trucks lined up ready to haul the grain away, Maxar said.
Syria and Russia are staunch allies.
The company said another image from June also showed a different ship being loaded with grain in Sevastopol.
Ukraine has accused Russia of stealing grain from the territories that Russian forces have occupied since their invasion began in late February.
US Agriculture Secretary Tom Vilsack said on Thursday temporary silos on Ukraine's border could prevent Russia from stealing Ukrainian grain and make sure the country's winter harvest was not lost due to a lack of storage.
During a visit to the United Nations, Mr Vilsack stressed that reviving shipments from Ukraine's Black Sea ports was the most effective and efficient way to export grain and he urged Russia to take UN-led talks on the issue "seriously".
"We know of circumstances and situations where that has occurred — Russians having taken grain from Ukrainian farmers. So to the extent that we can get it out of the country, that is a plus that reduces the risk of loss," Mr Vilsack said.
The war threatens to cause severe food shortages, with Russia and Ukraine accounting for about 29 per cent of global wheat exports.
Ukraine is one of the world's largest grain exporters, and Western countries have accused Russia of creating the risk of global famine by shutting Ukraine's Black Sea ports.
On June 8, the deputy head of Ukrainian agriculture producers union UAC said Russia has stolen about 600,000 tonnes of grain from occupied territory and exported some of it.
Russia calls its action in Ukraine a "special military operation" saying its aim is to disarm and "denazify" its neighbour.
The West and Ukraine say this is a pretext for unprovoked aggression.
Reuters/ABC
