U.S. bringing instability to regional situation, says China

China on Saturday called on the United States to stop issuing "wrong remarks" about the disputed Senkaku islands, located in the East China Sea and known as the Diaoyu in China.

The Chinese Foreign Ministry said in a statement that the U.S. should avoid complicating the issue and "bringing instability to the regional situation", reports the Guardian.

This comes after U.S. Defence Secretary James Mattis, during his two-day visit to Japan, said the islands, which are controlled by Japan but also claimed by China, fell within the scope of the Japan-US security treaty, under which Washington is obliged to defend all areas under Japanese administrative control.

Mattis also made clear that the U.S. opposed any unilateral action that risked undermining Japan's control of the Senkakus.

"I want to make certain that Article 5 of our mutual defence treaty is understood to be as real to us today as it was a year ago, five years ago - and as it will be a year, and 10 years, from now," Mattis, Japanese Prime Minister, Shinzo Abe, on Friday evening.

"I want there to be no misunderstanding during the transition in Washington that we stand firmly, 100% shoulder-to-shoulder with you and the Japanese people," he said.

Earlier in the week, Mattis issued similar reassurance to South Korea and warned North Korea that any use of nuclear weapons would be met with an "effective an overwhelming response".

The decision to make Japan and South Korea Mattis's first overseas destination as Defence Secretary is seen as an attempt to calm U.S. allies as last year Trump suggested that Washington could significantly roll back its military presence in the region, despite growing concern over Chinese island building in the South China Sea and North Korea's nuclear and ballistic missile programmes.

On Friday, Mattis said the US had an "ironclad" commitment to defending its allies in Asia, and warned North Korea that any attempt to use nuclear weapons would invite a severe response.

"Any attack on the United States, or our allies, will be defeated, and any use of nuclear weapons would be met with a response that would be effective and overwhelming," he said in Seoul.

In addition to friction over the Senkaku and the South China Sea, Beijing has also criticised the deployment of terminal high-altitude area defence (THAAD) in South Korea saying the system could upset the balance of power in the region.