China will boost offshore surveillance by adding ships and 6,000 personnel by 2020, state media said on Friday, another move likely to raise tensions with neighbours staking rival claims to waters thought to hold vast reserves of oil and gas.
The expansion of the China Maritime Surveillance Forces, a paramilitary law enforcement agency that patrols China's territorial waters, was unveiled two days after the country sent its largest civilian maritime patrol ship to the South China Sea.
The moves show Beijing's resolve to protect its "maritime rights and sovereignty" which it says have been increasingly violated amid a rising frequency of disputes.
The maritime surveillance forces, under the State Oceanic Administration, will have 16 aircraft and 350 vessels by the end of the country's five-year plan ending in 2015, and more than 15,000 personnel by 2020, the official China Daily said citing an unnamed senior official.
"There have been an increasing number of intrusions by foreign vessels and planes into Chinese waters and airspace in recent years," the newspaper said.
It said that the maritime surveillance forces had logged 1,303 foreign ships and 214 planes intruding in 2010, compared to a total of 110 cases in 2007.
Tensions in the South China Sea have risen in the past month on concerns China is becoming more assertive in the waters, parts of which are also claimed by the Brunei, Malaysia, the Philippines, Taiwan and Vietnam.
China's claim is by far the largest, forming a large U-shape over most of the sea's 648,000 square miles (1.7 million square km), including the Spratly and Paracel archipelagos.
This week, Beijing warned outside countries not to step into the dispute, after Vietnam said other countries, including the United States, could help defuse the tension.
China has accused Vietnam of violating its claim to the Spratlys and nearby seas, which Vietnam also deems its own. China calls the islands the Nansha group.
Beijing said last week it would hold naval drills in June in the western Pacific Ocean and the navy has done little to disguise plans to launch its first aircraft carrier.