South China Sea
South China Sea Reuters

China urged Japan to refrain from causing trouble in the South China Sea and to respect related countries' efforts to maintain peace and stability on the disputed waterway. Beijing pledged to have a firm response if Tokyo stirs up any further issues.

Chinese Foreign Ministry spokeswoman Hua Chunying said at a media briefing on Thursday that Japan has recently been compromising stability in the South China Sea, based on its own interests" causing strong dissatisfaction and opposition from the Chinese people."

"If Japan persists in taking wrong actions, and even considers military interventions that threaten China's sovereignty and security... then China will inevitably take firm responsive measures," she said.

The comments came after Reuters reported on a Japanese plan to send its largest warship to the conflicted waters of South China Sea. Sources told Reuters that the Izumo helicopter carrier, commissioned only two years ago, will make stops in Singapore, Indonesia, the Philippines and Sri Lanka, before joining the Malabar joint naval exercise with Indian and US naval vessels in the Indian Ocean in July. According to reports, the trip would be Japan's biggest show of naval force in the region since World War II.

"Japan should reflect deeply"

On Tuesday, China already said that it was waiting for an official confirmation on whether the report was correct, and why Japan plans to send the warship on the tour through the South China Sea. It hoped that Japan would be responsible.

Hua did not say on Thursday if China had received confirmation of the plan, but she said that the South China Sea issue did not involve Japan and that the country should "reflect deeply" on its "disgraceful" past invasion of the Paracel and Spratly Islands which China claims as its own.

Japan controlled the islands during World War II until it surrendered in 1945. China claims almost all of the South China Sea, which has rich fishing grounds, oil and gas deposits, and through which around $5 trillion of global sea-borne trade passes each year, despite competing claims from Vietnam, the Philippines, Taiwan, Malaysia, and Brunei.

Japan interfering in South China Sea disputes?

Japan does not have any claim to the waters but has a separate maritime dispute with Beijing in the East China Sea. According to China, the dispute should be resolved without interference from non-claimants. But, Japan has repeatedly angered Beijing by criticizing its actions regarding the South China Sea disputes.

Since 2010, China has taken initiative to avoid conflicts in the South China Sea by speaking with 10 members of Asean to agree to a set of rules. Chinese Premier Li Keqiang addressed a news conference on Wednesday at the end of the annual meeting of China's parliament and said that China hopes to push forward with the negotiations for the code of conduct to maintain stability.