On Monday, the United States expressed its “deep concern” after China test-fired a “strategic” missile carrying a warhead from a submarine in the Pacific Ocean.

A US State Department statement said: “At a time when the United States is making more determined efforts than ever to prevent nuclear proliferation, China is doing exactly the opposite. The rapid and mysterious expansion of Beijing’s nuclear arsenal is a source of grave concern for the region and the world.”

The Chinese Navy announced, on Monday, that “at 12:01 p.m. on July 6, a strategic nuclear submarine belonging to the Chinese People’s Liberation Army Navy successfully launched a strategic missile carrying a training warhead toward the high seas in the Pacific Ocean,” explaining that it “landed accurately in the specified maritime area.”

In its statement, the US State Department called on China to “engage in substantive discussions on arms control.”

Last February, the United States called for the launch of multilateral negotiations to limit nuclear weapons, including Beijing, after the expiration of the “New START” treaty between Washington and Moscow, which raised fears of a nuclear race.

The New START Treaty was the last arms control treaty between the two major nuclear powers, the United States and Russia.

Washington accuses Russia and China of conducting secret experiments.

On the other hand, President Donald Trump announced last October that the United States was preparing to resume its first nuclear tests since 1992, in response to tests conducted by other countries.