Wheat prices, showing signs of Russia’s continued commitment to its war in Ukraine, recorded the biggest increase in more than a week.

Chicago wheat futures rose by 3.1% on Tuesday, the largest increase since September 6.

Prices had fallen last week and ahead of weekend talks between U.S. envoys and Vladimir Putin.

CRM Agri Commodities wrote in a note: “Hopes for a real breakthrough in Russia and Ukraine’s peace talks over the weekend gave way to the familiar disruption in Black Sea grain shipments.”