LONDON: Wheat prices rose to a 14-year high on Wednesday as the conflict in Ukraine raised major concerns about the availability of supplies from the Black Sea region.

Russia and Ukraine account for about 29% of global exports.

"Global buyers of grains have been increasingly turning to the U.S., Europe or South America to secure supplies in the immediate term, given the ongoing conflict," ING said in a note.

"The demand for stockpiling has also increased due to the current uncertainty, as prolonged military action in the region could create long-term supply imbalances."

The most-active wheat contract on the Chicago Board of Trade rose 5.7% to $10.40-1/4 a bushel by 1217 GMT after earlier peaking at $10.59 a bushel, its highest level since March 2008.

European wheat futures also surged, with the spot March contract on Paris-based Euronext climbing to a record high of 390 euros a tonne.

"Ukraine had announced at the beginning of the week that it would be keeping its Black Sea ports closed until the end of the Russian invasion, meaning that no wheat shipments can be sent from Ukraine by sea for an indefinite period," Commerzbank said in a note.

"Russia is also likely to find it difficult to export wheat because hardly any ships will be willing to travel into the crisis region, and insurance companies will doubtless demand significantly higher premiums to cover this."

Investors also worry the conflict may prevent farmers in Russia and Ukraine from planting crops like corn this spring.

The most active CBOT corn contract peaked at $7.47-3/4 - the highest level since December 2012 - but then slipped back to stand 0.5% lower at $7.22 a bushel.

The most active CBOT soybean contract fell 1.1% to $16.71-1/2 a bushel.