Wheat prices have surged to their highest level in five months after Russia attacked a port on the Danube river, intensifying efforts to cripple a vital export route for Ukrainian grain to reach world markets.

A drone attack on Monday hit the Danube port of Reni, destroying a grain hangar. It is one of Ukraine’s biggest river ports for grain.

It comes about a week after Moscow ended its involvement in the Black Sea Grain Initiative - a deal that allowed Ukraine to ship its crops across the waters - and subsequently attacked Odesa ports.

Michael Magdovitz, a senior commodity analyst at Rabobank Group, said: “This strike on the Danube is a huge deal.”

He said wheat is likely to be most affected by any shutoff in export capacity, followed by corn.

Vegetable oils may still be transported on truck and train, but it is less cost effective for grains to be exported that way, Mr Magdovitz added.

Wheat futures climbed as much as 2.6pc in Chicago to $7.7725 a bushel, the highest since February 21. 

Futures jumped by the exchange limit the previous day. Corn for December delivery rose as much as 0.7pc.

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