Ukraine said on Wednesday that Russia had struck port infrastructure in Ukraine's southern region of Odesa, targeting facilities used to export grain since the collapse of the deal allowing shipments from the Black Sea.
"On the night of August 2, Russian armed forces carried out a drone attack on Odesa," the general prosecutor's office said in a statement.
"The enemy attacked port facilities and industrial infrastructure of the Danube."
As a result of the attack, a grain elevator, grain silos and warehouses were damaged or destroyed, prosecutors said.
The Izmail district prosecutor's office has opened a probe, the statement added.
Romania's President Klaus Iohannis, whose country borders the southern tip of Ukraine along the Danube, called Russia's repeated attacks on Ukraine's Danube infrastructure "unacceptable", alleging they were "war crimes".
"Russia's continued attacks against the Ukrainian civilian infrastructure on Danube, in the proximity of Romania, are unacceptable," Iohannis posted on social media.
"These are war crimes and they further affect [Ukraine's] capacity to transfer their food products towards those in need in the world."
Russia has been pounding the port city of Odesa and the surrounding region since Moscow withdrew from a grain deal last month that allowed Kyiv's grain exports via the Black Sea to continue despite the war.
The Danube river port of Izmail is now the main export route for Ukrainian agricultural products.