About 100 Chinese fishing boats have been detected encroaching in Malaysia's waters in the disputed South China Sea, Malaysia's state news agency and a coast guard official said Friday.

The reported encroachment on Thursday is the latest action by Chinese vessels to raise concern in Southeast Asia, where four countries object to China's claim to virtually the whole of the South China Sea.

Malaysia's national security minister, Shahidan Kassim, said assets from the Malaysian Maritime Enforcement Agency and the navy have been sent to the area near the Luconia Shoals to monitor the situation, the Bernama news agency reported.