By Chris Buckley
BEIJING, Jun (Reuters) - China has sent its biggest civilian patrol ship across the South China Sea, state media said on Thursday, a move likely to raise tensions with neighboring countries sharing conflicting claims to waters thought to hold vast reserves of oil and gas.
The civilian sea patrol vessel left south China on Wednesday and will head south to Singapore passing near island groups at the heart of disputes with Vietnam and the Philippines.
The Haixun 31 maritime patrol ship weighs 3,000 tonnes, has a helicopter launch pad and can stay at sea for 40 days at a stretch, the official Beijing Daily reported.
"Our country's biggest maritime patrol ship patrols the South China Sea," said the headline of the paper.
China's move comes after weeks of trading accusations with Vietnam and the Philippines over what each government sees as intrusions and illegitimate claims over its territorial waters by the other in a stretch of ocean spanned by key shipping lanes.
Official Chinese media reports about the ship's journey did not mention those disputes specifically, but made plain the patrol is meant to show Beijing's resolve to defend its territorial claims.
"Throughout its journey, it will carry out patrolling of the marine areas being developed by China in the South China Sea," said the Takung Pao, a Chinese-language Hong Kong newspaper that is under mainland control.
"It will protect national maritime rights and sovereignty," said the paper.
The South China Sea tensions have been magnified by region-wide nervousness about China's naval modernization.
China has accused Vietnam of violating its claim to the Spratly archipelago and nearby seas, which Vietnam also deems its own. China calls the islands the Nansha group.
China, the Philippines, Malaysia, Brunei and Taiwan all claim territory in the South China Sea.
China's claim is by far the largest, forming a vast U-shape over most of the sea's 648,000 square miles (1.7 million square km), including the Spratly and Paracel archipelagos.
Beijing said last week it would hold naval drills in late June in the western Pacific Ocean, and the Chinese navy has done little to disguise plans to launch its first aircraft carrier, the first step toward building an operating carrier group.
(Reporting by Chris Buckley; Editing by Nick Macfie)