China has reportedly test-fired a new variant of its 10,000km-range Dongfeng missile, near the disputed South China Sea.
Unidentified Pentagon officials were quoted by the Washington Free Beacon as saying that China tested its DF-41 missile with two vehicles this week.
According to the South China Morning Post, testing for the mobile intercontinental ballistic missile (ICBM) shows that China is reinforcing its nuclear deterrent.
The missile was observed in flight by US military satellites and other regional sensors, reported the publication.
In a statement the People's Republic of China (PRC) Information Affairs Bureau of the Ministry of National Defense (MND) said: "It is normal for China to execute scientific experiments within its territory, and these experiments are not aimed at any specific country nor target.
"The so-called test location reported by the media is pure conjecture,"
In December 2015, China tested a rail-based DF-41 launcher.
The missile's sea-based version, the JL-2, can be launched from the PLA Navy's Type 094 nuclear submarines, reported the publication.
The US and South Korea are currently in discussions over the possible deployment of a Terminal High Altitude Area Defense (THAAD) missile defence system.