The armed forces have vowed to "fulfill their duty" to safeguard China's territory in the South China Sea, a Defense Ministry spokesman said on Thursday.

China's "Harbin" guided missile destroyer [File photo]

"China's military forces will collaborate closely with related governing bodies, including fishery administration and maritime law enforcement, to jointly ensure the country's maritime rights and interests," Geng Yansheng said in Beijing at a monthly press briefing of the Ministry.

This was the first official remark from the armed forces following a standoff with a Philippine warship in waters off China's Huangyan Island on April 10.

Analysts said the comments were also in response to growing domestic demand to ensure sovereignty in the South China Sea.

Earlier, Defense Minister Liang Guanglie said that any military action will be based on the needs of diplomacy.

Media reports said that China has sent a nuclear-powered submarine to the South China Sea, but the spokesman did not confirm or deny the accuracy of the reports.