The United States has asked major Korean shipbuilders to provide information on their capacity to build naval vessels, including destroyers and fleet replenishment ships, industry sources said Wednesday. The U.S. Department of Defense and the Navy recently sent requests for information (RFIs) to HD Hyundai Heavy Industries Co. and Hanwha Ocean Co., and the two companies submitted details on their destroyer design capabilities and shipbuilding capacity last month, according to the sources familiar with the matter. For a separate RFI on medium-sized naval tankers, the two shipbuilders and Samsung Heavy Industries Co. also submitted responses, they noted. "We responded to the U.S. RFIs by providing a comprehensive overview of the shipyards' capabilities, including their shipbuilding track record, design workforce and expertise, and annual shipbuilding capacity," an industry official said, asking for anonymity. Under the U.S. Federal Acquisition Regulation, an RFI is a procedure used by the government to gather pricing, delivery terms and other market information for planning purposes. The la