CHICAGO, Nov 7 (Reuters) - Chinese importers bought around 10 cargoes of U.S. soybeans on Tuesday, or about 600,000 metric tons, for shipment from Gulf Coast and Pacific Northwest export terminals between December and March, trade sources said.

If confirmed, it would be the largest single-day soybean purchase by the world's top soy importer in at least three months, according to U.S. Department of Agriculture data.

The bulk sales are the latest in a series of import deals since late last week by Sinograin, China's state-owned importer, according to three export traders with knowledge of the deals. Total purchases over that time were estimated at as much as 20 to 25 cargoes, two traders said.

U.S. prices have become more competitive with top soy exporter Brazil for shipments from December through March, when Brazil's next harvest will be available. (Reporting by Karl Plume in Chicago Editing by Marguerita Choy)