US wheat futures jumped 6%, hitting a two-week high, and corn rose more than 1% on Monday as Russia's withdrawal from a Black Sea export agreement raised concerns over global supplies, reported Reuters.

Soybeans followed the trend, with the most-active January contract setting a one-month top.

As of 1:08 p.m. CDT (1808 GMT), Chicago Board of Trade December wheat was up 54 cents at $8.83-1/4 per bushel after reaching $8.93-1/4, the contract's highest since October 14.

Benchmark CBOT wheat futures hit a record high of $13.63-1/2 a bushel in March.

CBOT December corn was up 10-1/2 cents at $6.91-1/4 a bushel and January soybeans SF3 were up 17-1/4 cents at $14.17-1/2 a bushel.

"The grain and oilseed markets rose sharply overnight, led by wheat, as food shortage fears rise again after Russia pulls out of the Black Sea trade agreement," StoneX chief commodities economist Arlan Suderman said in a client note.

Moscow suspended its participation in the Black Sea deal on Saturday in response to what it called a major Ukrainian drone attack on its fleet in Russia-annexed Crimea.

Ships carrying grain sailed from Ukrainian ports on Monday, suggesting Moscow had stopped short of reimposing a blockade.

But shipments could be interrupted again, not least if insurers stop underwriting them. Lloyd's of London insurer Ascot is suspending writing cover for new shipments using the Ukrainian grains corridor in the Black Sea until it has more clarity about the situation there, a senior official said.

Russia's moves overshadowed market pressure from a firmer dollar, which tends to make US grains less competitive globally, and seasonal pressure from the ongoing Midwest harvest.

Ahead of the US Department of Agriculture's (USDA) weekly crop progress report due later on Monday, analysts surveyed by Reuters on average expected the government to report the US corn harvest as 75% complete and the soybean harvest as 89% complete.

In its first condition ratings for the 2023 winter wheat crop, analysts on average expected the USDA to rate 41% of the crop in good to excellent condition. Approximately 74% of the US winter wheat crop was in an area experiencing drought as of October 25, the government said.

In South America, where roadblocks in at least 12 Brazilian states by truckers who support outgoing President Jair Bolsonaro could affect agricultural exports in one of the world's top food producers, according to the head of a key state farm lobby.