Japanese Prime Minister Shinzo Abe warned China against any attempt to land on the disputed Senkaku Islands, saying Japan would respond with force.
The prime minister issued the warning in Parliament in response to a question about what he would do if the Chinese land on the islands, the BBC reports:
"Since it has become the Abe government, we have made sure that if there is an instance where there is an intrusion into our territory or it seems that there could be landing on the islands then we will deal with it strongly," he said.
The warning came as eight Chinese ships sailed around the islands - called Senkaku in Japan and Diaoyu in China.
The Japanese coast guard said it was the highest number of Chinese boats in the area since Tokyo nationalised part of the island chain in September 2012.
As part of a treaty signed in the 1800s, China claims the islands, which lie in the South China Sea between Japan, Taiwan, and China, and have been an escalating source of tension over the past year.
Japan has administered the islands since Okinawa was returned to the country in 1972.