Russia has been condemned for launching a drone attack on a Ukrainian grain storage facility just 200 metres away from Romania.
Romanian president Klaus Iohannis said the strike on the port of Reni, across the Danube river, poses "serious risks" to the security of the Black Sea region and further impacts global food security.
As a member of Nato, if an attack were to spill over into Romanian territory, it would raise the possibility of dragging the Western military alliance into a wider conflict.
Wheat prices rose more than 8% after Russia’s attack on the Danube, a key thoroughfare for transporting Ukraine's grain around the world during the war.
The river route often carries 2 million metric tons of grain a month to Romania’s Black Sea ports for export.
Another grain depot was also destroyed in the Black Sea port of Odesa, which has been the target of bombardments almost every night.
It comes a week after Russia pulled out of a landmark deal - brokered by Turkey and the UN in July last year - allowing Ukraine to export grain through the Black Sea.
Known as the "breadbasket of Europe", Ukraine produced enough food to feed 400 million people per year before the war, according to the World Food Programme.
Production in the war-torn country has plummeted since then - with US officials estimating a fall from 33 million tonnes in 2021/22 to 17.5 million tonnes in 2023/24 - the smallest crop in over a decade.
Strikes on grain facilities and an uncertainty of shipments through the Black Sea will have implications across the world, with the International Rescue Committee warning more than 40 million lives could be at risk in East Africa due to hunger.
Condemning the latest strikes, Romanian prime minister Marcel Ciolacu tweeted: "The deterioration of global food security is one of the multiple consequences of the war of aggression launched by the Russian Federation against Ukraine.
"Romania will continue to support Ukraine in order to identify practical solutions for the continuation of additional grain exports to global markets."
Russia blamed "hidden Western sanctions" holding back its own fertiliser and wheat exports for its withdrawal from the deal.
However, according to the United States Department of Agriculture, it managed to solidify its status as the world's top wheat exporter in 2022/23, with its total supply exceeding 100 million tonnes for the first time.
Monday's strike was the latest in a barrage of attacks that has damaged critical port infrastructure in southern Ukraine in the past week.
The Kremlin has described the strikes as retribution for last week's Ukrainian strike on the crucial Kerch Bridge linking Russia with Crimea.
It raises questions about a crucial alternate route for Ukraine's vital grain exports.
Other routes by road and rail through Europe will heap on transportation costs and likely lead to lower production by Ukrainian farmers, analysts say.
Those avenues also have stirred divisions within the European Union.
On Sunday, at least one person was killed and 22 others wounded in an attack on Odesa that severely damaged 25 landmarks across the city, including the Transfiguration Cathedral.
UNESCO strongly condemned the attack on the cathedral and other heritage sites and said it will send a mission in coming days to assess damage.
Odesa’s historic centre was declared a UNESCO World Heritage site earlier this year, and the agency said the Russian attacks contradict Moscow’s pledge to take precautions to spare World Heritage sites in Ukraine.
The Russian military denied that it targeted the Transfiguration Cathedral, claiming without offering evidence that it was likely struck by a Ukrainian air defence missile.
Kremlin spokesman Dmitry Peskov on Monday echoed that claim, insisting without any evidence that the accusations against Russia “are an absolute lie.”
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