Wheat sent to Syria from the Black Sea port of Sevastopol in Crimea increased 17-fold this year to just over 500,000 tons, previously unreported Refinitiv shipping data shows, to make up nearly a third of the country's total imports of the grain.

With sanctions making it more complicated for Syria and Russia to trade using mainstream sea transport and marine insurance, the two countries are increasingly relying on their own ships to move the grain, including three Syrian vessels that are subject to sanctions imposed by Washington, the data shows.

Russia annexed Crimea in 2014. Russian forces invaded more of Ukraine on Feb. 24.

Both Ukraine and the Russia-installed authorities agree that some grain has been exported from occupied Zaporizhzhia via Crimea. Ukraine though says grain was stolen by the occupiers, a charge Russia denies.

Ukraine says at least a part of the grain that passed through Sevastopol was taken from Ukrainian territories after Russia invaded. Ukraine's embassy in Beirut, which has been tracking shipments coming to Syria, estimates that 500,000 tons of what it calls plundered Ukrainian grain has arrived in Syria since the invasion, shipped from several ports.

The embassy said these calculations and Ukrainian authorities' allegation that grain was stolen was based on information from field and silo owners in occupied territories, satellite data of truck movements to ports and the tracking of ships.