Chinese trawlers are active in the South China Seas
China plans to step up naval patrols in disputed waters in the South China Sea to protect its interests, Chinese state media quoted an official as saying.
The fisheries administration chief cited an increase in illegal fishing and other countries' "unfounded claims" in seas that China claims as its own.
China sent a fisheries patrol ship to the South China Sea last week, and said it could deploy more similar vessels.
The patrols come after US and Chinese ships were involved in a confrontation.
"Faced with a growing amount of illegal fishing and other countries' unfounded territorial claims it has become necessary to step up the fishery administration's patrols to protect China's rights and interests," the China Daily quoted official Wu Zhuang as saying.
"China will make the best use of its naval ships and may also build more fishery patrol ships, depending on the need," said Mr Wu, head of the fisheries administration in the South China Sea.
China claims an economic exclusion zone around its coast, and also claims much of the South China Sea islands in the Spratly and Paracel island groups.
SOUTH CHINA SEA TENSIONS
Territorial claims from China, the Philippines, Taiwan, Brunei, Vietnam and Malaysia overlap in resource-rich sea
Hosts some of the world's busiest shipping lanes
China says the US was in its Exclusive Economic Zone - but the two sides disagree on what activities are allowed in an EEZ
The atolls and reefs are thought to sit above large reserves of oil and gas and are claimed in whole, or in part by most countries in Asia.
Parts of them were defined as belonging to the Philippines in a law passed in its capital, Manila, last week - a move which Beijing called "illegal and invalid".
In an incident earlier this month, the US Navy complained that a naval survey vessel was "harassed" by Chinese ships in what it called international waters off Hainan Island, south China.
China rejected the complaint, accusing the US of breaking international law by operating in its Exclusive Economic Zone. The two nations later agreed to try to avoid rows.
Analysts say so many overlapping claims makes further confrontations likely.