China said Friday that its maritime defense forces recently staged three days and nights of exercises in the South China Sea, a disputed, resource-rich region where tensions are rising.

The drills involved a total of 14 patrol boats, landing craft and submarine hunting boats, along with two military aircraft, the official People's Daily newspaper said. It said the exercises were aimed at refining anti-submarine, replenishment and island defense capabilities in order to better respond to any future sudden crisis.

The vast South China Sea and its island groups form one of Asia's most politically sensitive regions, with China, Vietnam and the Philippines trading diplomatic barbs recently over overlapping territorial claims. Vietnam's navy conducted live-firing exercises Monday after accusing Chinese boats of disrupting oil and gas exploration in its waters.

The People's Daily said naval forces participated alongside units from nominally civilian agencies that are tasked with overseeing China's interests at sea.

The paper did not say exactly when or where the exercises took place, although a graphic accompanying the story implied they were held near the Spratly Islands, where China, Taiwan, the Philippines and Vietnam all maintain garrisons.

In addition, the military's official Liberation Army Daily newspaper reported that an exercise was held on June 6 in which amphibious vehicles — most likely tanks — were successfully offloaded from ships onto a South China Sea island. No other details were given, and it was unclear whether the exercise was among those the People's Daily reported.

China claims the entire South China Sea and all its island groups, but maintains garrisons on only a few atolls, islets and partially submerged corral reefs.

The report of the exercises follows the dispatch Wednesday of one of its largest maritime patrol ships on a first-ever visit to Singapore, a voyage in which it will transit the South China Sea.

The Haixun-31 was due to stay in the Southeast Asian city-state for two weeks of exchanges on search and rescue, anti-piracy and port management operations.