CHICAGO, July 2 (Reuters) - With U.S. beef prices soaring and supplies tight, the U.S. Department of Agriculture surprised meat producers and traders on Thursday by reporting a spike in the nation's export sales, fueling questions over the accuracy of the data.

The beef export sales, reported in weekly USDA data, included deals that may have taken place months ago, contributing to the sudden increase, the agency told Reuters. Traders said the totals still looked excessive.

U.S. beef exports have declined since 2022 due to high prices and scarce inventories, and an increase could further raise costs for domestic consumers already facing higher grocery bills during the summer grilling season.

Beef prices broke records this year due to strong demand and a persistent drought that drove U.S. ranchers to slash their cattle herds.

USDA said in its report that net export sales of U.S. beef for delivery in 2026 reached 126,062 metric tons in the week ended June 25, a marketing-year high that was up almost 500% from a week earlier. The figure may include several months of data, the agency later said in an email.

"Sales and exports are required to be reported in the week in which the sale and export take place," USDA told Reuters. "Unfortunately, there was a misunderstanding on the reporting requirement, and the sales and exports were held for several reports before being reported."

Of the total, net sales and exports of 111,164 metric tons were reported late, including 38,452 metric tons sold to Chile and 32,246 metric tons sold to Italy, USDA said on its website.

Both totals would shatter previous annual U.S. beef export records. The U.S. exported 12,885.4 metric tons to Chile in 2013 and 6,998.7 metric tons to Italy in 2012, according to U.S. Census Bureau trade data.

"None of those numbers make a lot of sense," said Matt Wiegand, commodity broker for FuturesOne.

Altin Kalo, head economist at Steiner Consulting Group, said he thought the data was mistakenly entered into USDA's reporting system in kilograms instead of metric tons, causing sales to look bigger than they were.

"That's the only thing that would make sense ... that they reported the wrong units," he said.

USDA said it confirmed with an exporting company that the quantities were correct and reported as metric tons.

"Barring any further confusion, next week's ... beef quantities should look 'normal,'" the agency said.