Russian forces attacked the main Ukrainian port on the Danube on Wednesday morning, destroying several buildings and disrupting grain exports. 

It is the latest escalation by Russia against the Ukrainian exports industry, two weeks after it withdrew from the UN grain deal, which had protected Ukraine-bound shipping in the Black Sea. 

Ukrainian officials said 40,000t of grain were damaged in the drone attack on Izmail, but no casualties were reported. 

"Russian terrorists have once again attacked ports, grain and global food security," President Volodymyr Zelenskiy said on Telegram.

The route north up the Danube is a vital alternative route for Ukraine’s exports, but it has been effectively shut off by the assault. 

Ship tracking information shows a long queue of ships destined for Izmail at anchor on the Romanian bank of the river and a build-up of vessels waiting to approach the port from the Black Sea. 

It is unclear if the port has returned to full capacity, but Seaport authority head Yuriy Lytvyn said on Facebook the freight infrastructure continued to operate. 

The attack came before Russia’s President Vladimir Putin spoke via telephone with Turkey’s President Recep Tayyip Erdoğan to discuss the conditions of resuming the grain deal. 

Global grain markets reacted swiftly, prices jumped 4% in Chicago and maize followed at 2%, according to the Financial Times.