China is scooping up U.S. corn and soybeans as part of efforts to mitigate the risks to commodity supplies from Russia’s war in Ukraine and slower harvests in South America.

Chinese buyers recently booked about 20 cargoes of American soybeans and about 10 shipments of corn, according to traders who asked not to be identified as they aren’t authorized to speak publicly. The buying spree reflects robust demand in the top importer as worries over supplies grow following Russia’s invasion of Ukraine and weaker-than-expected supply from Brazil, the world’s biggest soybean producer.

Those purchases come after the Phase-one deal agreement between China and the U.S. expired without agriculture targets being met. Through December, the U.S. exported $34 billion of agriculture to China, short of the $40 billion target, according to U.S. Census Bureau data. While both countries are talking about extending the deal, it’s expected that China will buy more American products to secure needed grain supply amid tight world stocks.

Russia and Ukraine are among the biggest exporters of major grains like wheat and corn, and also vegetable oils used in cooking. As shipments from the two countries grind to a virtual standstill, prices of many agricultural commodities have soared. China is a major buyer of corn and barley from Ukraine, as well as sunflower oil from both Ukraine and Russia.

Benchmark soybean futures rose as much as 2.2% Thursday in Chicago, while corn jumped 4.8%.

The U.S. soy purchases are for shipment from May onward, the traders said. That is unusual as Brazilian soybeans are historically cheaper than American for this time of year, right after the harvest that takes place in February and March and before the U.S. harvest in October and November.

Prospects of a record Brazilian soy crop this year were shattered by weather woes that ended up delaying the harvest, and exports, far behind initial estimates.

This lack of immediate supply is seen on huge ship lineups outside ports in Brazil as well in premiums for the crop. Brazilian soybean future contracts from Santos are higher than those from the U.S. Gulf this year—a sign that supplies from the world’s biggest producer and exporter are smaller and more demand should go to the U.S.

For corn, China is seeking to replace some supplies from Ukraine and also as a buffer against future production losses, the traders said. Ukrainian corn is usually planted in April and May, and the ravages of war, a shortage of farm workers and chaos around transportation and logistics may put those crops in jeopardy.

Brazil, usually the third or fourth biggest corn exporter, is struggling to replenish depleted stocks after a smaller-than-expected second corn crop harvest last May. The U.S. Department of Agriculture has lowered Brazil’s corn crop estimate to 114 million tons from its initial 118 million estimate.

Food security is a critical priority for Beijing as the nation’s imports of corn, soybeans and wheat have soared to record levels, increasing its vulnerability to trade tensions and supply shocks. Top officials have issued orders to ensure commodity supplies, sparked by concerns over Black Sea trade disruptions.