Russia said Monday it would not renew an agreement to safeguard cargo passage on a critical Black Sea shipping corridor that for months has helped to stabilize global food prices.

The announcement signals the resumption of a Russian naval blockade in Europe's breadbasket, primarily of Ukrainian wheat and corn. The cessation of the international deal revives a litany of concerns among Minnesota stakeholders in the region, ranging from food insecurity to endangered shipping vessels.

Calling on Russia to reverse the decision, Sen. Amy Klobuchar, D-Minnesota, put blame on Russian President Vladimir Putin for pulling out of the Black Sea Grain Initiative, which she said would exacerbate food insecurity.

"Putin's barbaric war continues to have global repercussions," Klobuchar said in a statement.

The Black Sea Grain Initiative, which was brokered last summer by Turkey and the United Nations, has for nearly a year allowed safe shipping passage out of the vital waterway from Ukrainian ports to straits in Turkey, enabling further access to the Mediterranean Sea.

The news, which initially spiked global wheat prices, renewed concern that the 19-month-old conflict could again hinder hunger relief efforts in Africa. Grain shipments from Ukraine undergird a staple of food aid programs to nations in East Africa, including Somalia and Ethiopia.

"Russia's termination of the Black Sea grain deal with Ukraine will lead to humanitarian catastrophe," Rep. IIhan Omar, D-Minnesota, said in a statement. "By terminating this deal, Putin is effectively plunging millions around the world into famine and starvation."

Russia's ending of a Black Sea deal was felt in Minnesota where agribusiness companies charter ships in European waters and farmers, facing soft commodity prices, looked at possible jumps in global demand.

But rather than watch the explosion of wheat and corn prices, analysts spent the day watching wheat prices dramatically rise and then, just as quickly, cool off.

By Monday afternoon, the Chicago Board of Trade saw wheat futures fall more than seven cents to $6.53 a bushel. Corn futures had dropped nearly eight cents during the day to $5.06 a bushel.

"I hate to say it's not a market factor, but at the moment, traders are kind of a cynical bunch. They're all saying Russia has cried wolf a bunch of times about this trade deal," Jason Ward, managing director of Minneapolis-based Northstar Commodity, said.

"I don't necessarily think we've heard the last of this. If it's a closed deal forever, it will be impactful of the Chinese, as they will have to make alternative arrangements for grain."

Stalled grain ships in Ukrainian ports — and the stalling of corn exports to global buyers such as China — could also unleash new tensions on the map of international relationships between countries.

"This is Putin exercising what he perceives as his power on the global stage," said Devry Boughner Vorwerk, CEO of DevryBV Sustainable Strategies and a former Cargill executive. "And I think this is very risky for Putin to endanger the food shipments because he loses his bargaining power."

Without corn from Ukraine, Ward said, buyers in China may lean more heavily on Brazil, possibly freeing up global demand for U.S. corn.

In the spring of 2022, domestic grain prices hit near-record highs with corn at $8 a bushel and wheat trading closer to $12 a bushel. But global food and commodity prices softened following the establishment of the humanitarian corridor.

According to the U.N. Food and Agricultural Organization's Food Price Index, food prices have dropped nearly 25% since March of 2022.

The unblocking of Ukraine's lucrative grain ships and ports also offered a financial lifeline to the besieged European country. But Russian leadership had complained that the deal has left in place restrictions on Russian agricultural exports, stymieing its own coffers in a time of war.

The grain deal, which was scheduled to sunset on Monday, had long been tenuous, Ward said.

Minnesota firms, such as Cargill and CHS, that operate agricultural systems, including shipping in the Black Sea, have experienced hazardous conditions since the beginning of the war.

In the early days of Russia's unprovoked invasion of Ukraine, a Russian missile struck an empty Cargill vessel on the Black Sea. This past spring, the Minnetonka-based global trader announced the company would no longer elevate Russian grain for export.

Executives at Inver Grove Heights-based CHS, which aided some employees to escape war-torn Ukraine in the war's beginning, spoke candidly last year about the challenges of transporting grain out of country on rail that historically would exit on larger, oceangoing vessels.

Without a sea route, grain haulers will need to likely send wheat and corn westward on train over the Ukraine border, only to be sent downstream on barges running the Danube River, taking more time and upping the per-bushel cost to move grain.

"As a result of this development, trade flows will likely shift, putting more importance on the grain coming out of the U.S. and South America," said Tom Ryan, a CHS spokesman. "Wheat and corn will continue to be transported from Ukraine to neighboring countries via trains, trucks and barges. However, we see this further limiting grain coming out of the country."

A representative for Cargill declined to comment.

Fears now have re-emerged that closing the corridor could deliver uncertainty and costly prices once again into global food systems.

Such a turnabout might be received positively by U.S. corn farmers, who've seen prices on corn drop since a year ago. But the return of high corn prices might further hamper efforts on livestock operations where animals eat feed comprising grain.

"Generally speaking, when grain prices go up with high interest rates, it'll hurt the dairy sector," said Lucas Sjostrom, executive director of Minnesota Milk Producers Association. Although Sjostrom noted many dairy farmers may also grow their own corn or wheat and benefit from any commodity price increase.