Businesses spent much of March awash in uncertainty about how the Iran war will affect their costs, customers and the broader economy, according to a survey from the Federal Reserve.

The central bank's anecdotal Beige Book, published Wednesday, showed that the Middle East conflict has quickly eclipsed other concerns as the overarching risk on many managers' minds. Often, companies have pressed the pause button as they await clarity on how long tensions will last.

"The conflict in the Middle East was cited as a major source of uncertainty that complicated decision-making around hiring, pricing, and capital investment, with many firms adopting a wait-and-see posture," the Fed's Beige Book reported.

Anxiety about the conflict was apparent across the country. Companies in the Northeast told the New York Fed that they "saw an increase in energy costs due to the conflict in the Middle East, including fuel surcharges," with one reporting that the price increases also extended to the cost of freight and agricultural ingredients.

In the Midwest, some companies told the Chicago Fed that they were facing potential shortages of some chemicals because of the conflict. The St. Louis Fed said the war had "created significant volatility in the agriculture sector, impacting agriculture equipment sales and resulting in sharp fertilizer cost increases."

The survey also showed why the conflict has landed at an especially challenging time for the economy, which has otherwise shown surprising resilience while weathering a slew of other risks. Across the country, many companies reported that while layoffs have remained minimal, they are mostly hiring only to replace staff who have left, not to expand. That accords with months of statistical evidence showing the economy has shifted into a low-hire, low-fire dynamic that has frustrated out-of-work jobseekers.

An apparel company told the Minneapolis Fed that it "would like to add staff but holding off due to economic volatility."

Meanwhile, consumer demand looks uneven. Many shoppers appear to be facing expenses that are straining their budgets after years of above-target inflation, showing increased sensitivity to price increases. The Fed reported rising demand across the country at food banks and other social-service organizations.

A jewelry store in Williamsburg, Va. told the Richmond Fed that if consumers "can save a dollar and get free shipping, they're shopping online...it's been my worst year so far. "