More Japanese firms shut their operations in China on Tuesday over a territorial dispute that has soured ties between Asia's two largest economies.
Japan's claim last week to have nationalised the uninhabited islands in the East China Sea has sparked anti-Japanese protests, some of them violent.
A number of Japanese businesses have been forced to close after acts of sabotage, including fashion retailer Uniqlo, carmaker Toyota and electronics firm Sony.
Trade between Japan and China is worth 260 billion euros and both economies are grappling with a global economic slowdown.
The row centres over the island chain which Tokyo calls Senkaku.
They are known as the Diayou islands by the Chinese, who argue the Japanese claim dates back to when its army invaded China in the 19th century.
Japan's coastguard said on Tuesday that Beijing has sent 11 warships to the islands, which are rich in fishing stocks and close to maritime oil and gas fields.
