Russia attacked Ukraine’s main inland port across the Danube River from Romania on Wednesday, sending global food prices higher as it ramps up its use of force to reimpose a blockade.

Ukraine’s defence ministry said a grain silo was damaged in the Danube port of Izmail in the Odesa region: “Ukrainian grain has the potential to feed millions of people worldwide,” the ministry wrote on messaging platform X.

The port, across the river from NATO-member Romania, has served as the main alternative route out of Ukraine for grain exports since Russia reintroduced its de facto blockade of Ukraine’s Black Sea ports in mid-July.

Video released by the Ukrainian authorities showed firefighters on ladders battling a huge blaze several stories high in a building covered with broken windows. Several other large buildings were in ruins, and grain spilled out of at least two wrecked silos.

There were no reports of casualties, Odesa region governor Oleh Kiper wrote in a post on the Telegram messaging app.

“Unfortunately, there are damages,” President Volodymyr Zelenskiy said on Telegram. “The most significant ones are in the south of the country. Russian terrorists have once again attacked ports, grain, global food security.”

An industry source also confirmed Izmail was the main target of the attack, describing the level of damage there as “serious”.

Chicago wheat prices jumped 4% following Wednesday’s attack and were still up around 2.5% later in the morning, with traders worried anew about a hit to global supplies from driving Ukraine, one of the world’s top exporters, off the market.

Russia has relentlessly attacked Ukrainian agricultural and port infrastructure for more than two weeks, since refusing to extend an agreement that had lifted its war-time blockade of Ukrainian ports last year.