China has urged Japan not to take any action that could endanger the safety of Chinese lives and property following a Taiwanese vessel's entry to waters near the Diaoyu Islands, a Foreign Ministry spokesman said Wednesday.

Spokesman Liu Weimin made the remarks at a regular press conference when asked to comment on a Taiwanese vessel entering waters near the Diaoyu Islands in the East China Sea.

Media reports said a fishing boat carrying Taiwanese activists was spotted sailing near the Diaoyu Islands Wednesday morning.

Officials from Taiwan's Coast Guard Administration said five patrol boats have been sent to protect the boat and the nine people on it.

The Diaoyu Islands and its affiliated islands have been China's inherent territory since ancient times and China has undisputable sovereignty over the islands, Liu said.

China will continue to take necessary measures to firmly safeguard its sovereignty over the Diaoyu Islands, he said.

"We have already urged the Japanese side to refrain from taking action that could endanger lives and property, including those of our Taiwanese compatriots," Liu stressed.