HAMBURG/CHICAGO, May 21 (Reuters) - Chinese importers are believed to have purchased at least two shipments of soybeans from the United States in the past few days, grain traders in Europe and the U.S. told Reuters on Tuesday.

The precise volume was unclear.

One European trader said two shipments each of about 65,000 metric tons were bought for July shipment.

A second European trader said two consignments were bought on Monday, also for July shipment from the U.S. Pacific Northwest coast, with the buyer believed to be a Chinese state organization purchasing for reserves.

The pace of China's buying of U.S. soybeans has slumped this year, as the world's top soybean purchaser has increasingly turned to cheaper supplies from South America. The U.S. Department of Agriculture also has not reported any U.S. soybean sales to China for the 2024-2025 marketing year, according to agency data.

Traditionally, Brazil ships most of its soybean crop from March to June. But floods in key producing state Rio Grande do Sul Rio have disrupted this season's harvest and led to cuts in the state's soy production estimates.

And over the past three weeks, export premium prices for Brazilian yellow soybeans have turned higher, prompting buyers to scout for deals elsewhere.

"Brazilian export premiums are firming sharply as their export season goes past its peak, so U.S. soybeans are looking more attractive," one European trader said. "This is opening a window for the U.S. but the Chinese are still buying in Brazil, though."

China's soybean imports from Brazil rose 11.7% in April from a year earlier, as fresh Brazilian beans continue to arrive at Chinese ports from flood-hit Brazil, Chinese customs data showed on Monday.

Meanwhile, Chinese soybean imports from the U.S. in the first four months of the year were down 40% from a year earlier. (Reporting by Michael Hogan in Hamburg, and P.J. Huffstutter and Karl Plume in Chicago; Editing by Will Dunham)