Global wheat prices rose sharply Monday following Russia’s withdrawal from the Black Sea grain export deal over the weekend.

The most active wheat contract on the Chicago Board of Trade jumped 5.8% to $8.77 a bushel by around 6 a.m. ET time after earlier hitting a high of $8.93 a bushel. Corn and soybean prices have also risen but to a lesser extent with corn futures up 2.6% and soybean futures climbing 0.7%.

The increases come after Russia announced Saturday that it was suspending its involvement in the Black Sea Grain Initiative, which allowed vital agricultural products to be exported from several Ukrainian ports.

Russia announced it was withdrawing from the deal for an indefinite period after it accused Ukraine of a “massive” drone attack on the Black Sea Fleet in Sevastopol in Crimea.

Ukraine has not said whether it was responsible for the attack and President Volodymyr Zelenskyy said Russia’s withdrawal from the initiative was “rather predictable.”

Ukraine’s Foreign Ministry said, meanwhile, that Russia had suspended its participation in the grain deal on “a false pretext of explosions 220 kilometers away from the grain corridor” and that by doing this, it was blocking “two million tons of grain on 176 vessels already at sea.”

Zelenskyy and Foreign Minister Dmytro Kuleba accused Russia of starting to sabotage the grain deal in September.

CNBC has contacted Russia’s Foreign Ministry for comment. Russia’s ambassador to the U.S., Anatoly Antonov, has hit back at Washington’s accusations that Russia is aggravating the global food problem. Antonov told Russian media on Saturday that Kyiv’s “reckless actions” had caused Moscow to suspend implementation of the grain deal.

Moscow has been accused of weaponizing key exports such as gas and wheat since the start of the war in February, both in a bid to pressure the international community and in order to receive sanctions relief. Moscow has denied this and accused Ukraine of mining its waters, hence preventing the safe export of agricultural produce such as wheat, corn and rapeseed that many countries rely upon.

Many of the grain ships that left Ukraine in recent months, under the grain deal, were bound for both European and African ports.

Ukraine’s president said Sunday night that Moscow’s withdrawal from the grain initiative, which was due to be renegotiated in November in any case, would exacerbate a global food crisis with countries in Africa, and particularly Ethiopia, at risk of a severe famine.

‘The food must flow’