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 coastguard official said on 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.
Shahidan did not specify what type of Chinese vessels had been spotted but a Maritime Enforcement Agency official said they were fishing boats guarded by two Chinese coastguard vessels.
China claims most of the South China Sea through which about $5 trillion in ship-borne trade passes every year. Its Southeast Asian neighbours Brunei, Malaysia, the Philippines and Vietnam, also claim parts of the sea, as does Taiwan.
China's foreign ministry spokesman, Hong Lei, asked about the Malaysian report at a briefing on Friday, said he did not "understand the details" of what Malaysia had said.
"Now is the fishing season in the South China Sea ... At this time of year, every year, Chinese trawlers are in the relevant waters carrying out normal fishing activities," Hong said. He did not elaborate.
Shahidan said Malaysia would take legal action if the boats were found to have trespassed into its exclusive economic zone, Bernama cited him as saying.
The Malaysian maritime agency official said three of its boats were monitoring the Chinese fleet.
"Our orders are not to provoke them in any way," said the official who declined to be identified as he is not authorised to speak to media.
This week, Indonesia protested to China about an incident involving an Indonesian patrol boat, and a Chinese coastguard vessel and fishing boat in what Indonesia said was its waters.
China has said its vessels were operating in its fishing grounds and its coastguard vessel did not enter Indonesian waters.
Indonesia is not embroiled in the rival claims and has instead seen itself as an "honest broker".
China says it is committed to resolving the disputes but only via bilateral talks. Speaking at a conference in China, Vice Foreign Minister Liu Zhenmin repeated that position.
"We rarely see multilateral negotiations are able to resolve complex and sensitive territorial and maritime boundary disputes," Liu said, according to a transcript provided by China's foreign ministry.
(Reporting by Rozanna Latiff in Kuala Lumpur and Ben Blanchard; Editing by Robert Birsel)