China has accused Japan of trying to "smear" Beijing's image, after Tokyo alleged a Chinese warship locked its weapons-targeting radar on a Japanese vessel near disputed islands.
Chinese Foreign Ministry spokeswoman Hua Chunying said Thursday the issue is not China displaying its strength, but Japanese ships and aircraft carrying out "illegal activities" that infringe on China's territorial sovereignty in the East China Sea.
She accused Japan of increasing tensions.
"The problem at present is not China showing strength, but Japan continuously sending its ships and aircraft into the waters and airspace around the Diaoyu Islands to carry out illegal activities, damaging and infringing upon China territorial sovereignty," Hua said. "Recently, Japan has been intentionally stirring up a crisis and causing tensions, blackening China's image. This is diametrically the opposite of efforts to improve relations.''
Hua also said China is investigating Japan's complaint that a Chinese navy frigate recently aimed its weapons-targeting radar at the Japanese vessel.
Japanese Prime Minister Shinzo Abe called the alleged Chinese action "dangerous" and said it could lead to an accidental clash.
The feud is the latest escalation in the long-running dispute between Japan and China about ownership of a group of East China Sea islands.
The uninhabited islands, known as Senkaku in Japan and Diaoyu in China, are surrounded by rich fishing grounds and possibly by energy deposits.
Chinese-Japanese ties sank to their lowest level in years last September, after Japan bought some of the islands from their private Japanese landowner. The move sparked days of angry protests in China. It also damaged trade ties between Asia's two largest economies.