BEIJING -- In response to Vietnam's request to overturn China's ban on fishing in the South China Sea, a spokesman of China's Foreign Ministry said here that it is China's regular measures to protect marine resources within its own territorial waters.

Qin Gang, spokesman of the Foreign Ministry, was quoted by Tuesday's Global Times as saying that China has "indisputable" sovereignty over the South China Sea islands, including Xisha and Nansha islands, and their adjacent waters.

"It's a regular and justified administrative measure of China to post a summer fishing ban within the South China Sea, with the aim of protecting the sustainability of marine life in this area," Qin said.

China officially imposed the ban on May 16 to prevent overfishing, and it has sent eight patrol ships to monitor 128,000 square kilometers of the South China Sea.

But the area, a huge exclusive economic zone surrounding the Nansha and Xisha islands, has long been coveted by Vietnam.

Vietnamese Deputy Foreign Minister Ho Xuan Son told China's ambassador to Vietnam Sun Guoxiang that increased Chinese patrols had led to more arrests and fines affecting "normal fishing activities by Vietnamese fishermen in Vietnam's traditional fishing grounds."

Zhuang Guotu, dean of the Research School of Southeast Asian Studies at Xiamen University, told the Global Times that China shows a firm attitude on the protection of its sovereignty over the South China Sea.

"Fishery resources are also safeguarded by the Chinese fishery administration vessels," Zhuang said.