TOKYO: Four Chinese government ships were in the territorial waters of disputed Tokyo-controlled islands on Friday, Japan’s coastguard said.

The maritime surveillance ships entered the 12-nautical-mile zone around one of the East China Sea islands, the coastguard said.

They were sailing near Uotsurijima, they said, referring to the main islet in the disputed chain, called the Senkaku Islands in Japan and the Diaoyu Islands in China.

Chinese vessels have moved in and out of what Japan says is its sovereign territory over the last two months, since Tokyo nationalized some of the islands.

As well as the potential mineral reserves to which ownership of the islands grants access, both countries have considerable amounts of national pride at stake in the decades-old spat.

The dispute has hit the huge trade relationship between the two largest economies in the region. Senior representatives from both governments are reportedly readying for a third round of talks on the issue.