China's ambassador to Japan is rejecting Tokyo's protest over the patrol of Chinese navy ships near a group of islands disputed by Japan, China and Taiwan.
Japan accused the Chinese navy of using radar to gather information on the location of a Japanese escort vessel and a helicopter. The type of radar used could be used to produce data needed to fire upon the Japanese equipment.
The Japanese foreign ministry summoned the Chinese ambassador for a meeting Tuesday to lodge a formal protest regarding the accusations.
The Chinese actions were unusual and one false step could lead to a dangerous situation, Japanese Defense Minister Itsunori Onoder said Tuesday.
China countered that it has been conducting regular patrols in Chinese waters and asked Japan not to interfere.
"We think the top priority for now is for Japan to stop all provocative actions it has been doing as sending ships and flights into Diaoyu islands sea and air space," Chinese foreign ministry spokesman Hua Chunying said, referring to the disputed islands. "We hope Japan can take actions to show sincerity and willingness to work with China through talks and negotiations to control and manage the current situation."
The Japanese call the uninhabited islands the Senkakus. Near them are important shipping lanes, rich fishing grounds and possible oil deposits.
Disagreement over who owns them strained relations between Japan and China during the latter half of 2012, and the dispute shows no signs of waning.
In another show of force, China's navy conducted drills in the South China Sea over the weekend, the state-run Xinhua news agency reported.
The drill included a scenario in which a helicopter crew identified a target and prepared to fire a missile, and another in which crews responded to a fire on a ship.
Protests flared across China in September, soon after Japan announced it had bought several of the disputed islands from private Japanese owners. The deal was struck in part to prevent the islands from being bought by Tokyo governor Shintaro Ishihara, who had called for donations for a public fund to buy them.
China was outraged, as were protesters who marched through several Chinese cities calling for boycotts of Japanese products and urging the government to give the islands back.
In December, the dispute escalated when Japan scrambled fighter jets after a Chinese plane was seen near the islands. A number of Chinese ships have also entered contested waters despite warnings from the Japanese Coast Guard.
China says its claim extends back hundreds of years. Japan says it saw no trace of Chinese control of the islands in an 1885 survey, so formally recognized them as Japanese sovereign territory in 1895. Japan then sold the islands in 1932 to descendants of the original settlers. The Japanese surrender at the end of World War II in 1945 only served to cloud the issue further.
The islands were administered by the U.S. occupation force after the war. But in 1972, Washington returned them to Japan as part of its withdrawal from Okinawa.
Taiwan, which Beijing regards as a breakaway province, also lays claim to the islands. But the self-governing island has seldom rigorously advanced its claims because of an unwillingness to risk its good relationship with Japan, said Alan Dupont, a strategic analyst at the University of New South Wales in Sydney.
He said last year that Taiwan's decision to become more assertive was a response to actions taken by China and Japan in the second half of 2012, as well as concerns over access to fishing and marine resources.