Russia attacked a key Ukrainian port today sending global food prices higher. 

The attacks halted ships in their tracks as they prepared to arrive there to load up with Ukrainian grain in defiance of a de-facto blockade Russia reimposed in mid-July.

Ukraine’s Deputy Prime Minister said warehouses and grain elevators were hit in the attacks and 40 thousand tons of grain were damaged.

The port, across the Danube river from Romania, is the main alternative route out of Ukraine for grain exports, since Russia’s blockade halted traffic at Ukraine’s Black Sea ports in mid-July.

Wheat prices rose by nearly 5% following the attack, due to concern about a hit to global supplies from driving Ukraine, one of the world’s top exporters, off the market.

Russia has 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.