Vietnam has protested a Chinese state oil company's posting of bids for energy development in the disputed South China Sea, according to a report of the Associated Press. China National Offshore Oil Corporation opened nine oil and gas lots for international bidders over the weekend. Foreign Ministry spokesman Luong Thanh Nghi said the lots lie entirely within Vietnam's 200-nautical mile exclusive economic zone and continental shelf. China's move was illegal and the bidding should cease immediately, said the statement from Nghi posted on the ministry's website late Tuesday. Vietnam and China are among six claimants to all or parts of the Paracel and Spratly island groups in the South China Sea. The area has rich fishing grounds and potential energy resources. In Beijing, Chinese Foreign Ministry spokesman Hong Lei told a news conference Wednesday that it was natural for China National Offshore Oil Corp. to seek bids to explore the areas. Hong said China hopes Vietnam "will not further complicate and aggravate the dispute."