U.S. corn futures extended gains on Thursday while wheat was nearly flat, supported by prospects of tight global supply and an uncertain production outlook as the Russia-Ukraine war continued to rattle grain markets.

The most-active corn contract on the Chicago Board of Trade (CBOT) climbed 0.5% to $7.81-3/4 a bushel while wheat was nearly unchanged at $11.25-1/2 a bushel. Soybeans rose 0.9% to $16.90-1/2 a bushel despite signs of slowing demand from China, the world's top buyer.

The war between Russia and Ukraine, the world's two major producers and exporters of grains, rages on, bolstering global cereal prices. "Markets remain extremely nervous, with a risk that the conflict between Ukraine and Russia will drag on," French consultancy Agritel said in a note. Buyers looked for grains from alternative origins while countries such as India prepared to meet rising global demand.

Dry weather in the U.S. Plains wheat belt threatens the size and quality of the crop. Talks to end a strike among grain-truck drivers in Argentina failed, raising a threat to corn and soy export during the key harvest season. China, the world's top soybean importer, brought in 6.35 million tonnes of the oilseed in March, down 18% on the year.

Poor hog margins curbed demand for soymeal in feed, as prices of the key protein ingredient remain elevated. Asian shares tracked Wall Street higher, while U.S. Treasury yields steadied and the dollar retreated, as the latest U.S. data raised the chances that inflation may be close to peaking, even as major central banks raise rates aggressively.

(Reporting by Hallie Gu and Dominique Patton in Beijing and Sybille de La Hamaide in Paris; Editing by Sherry Jacob-Phillips and David Holmes)