The US military and intelligence officials were caught off-guard by China's reported hypersonic missile test carried out in July at five times the speed of sound - an unprecedented feat, The Financial Times reported.
Experts from the Pentagon’s advanced research agency Darpa are struggling to understand how China managed to master a technology that allowed its hypersonic glide vehicle to fire a separate missile mid-flight over the South China Sea, people familiar with the matter told the outlet.
Among those baffled by the reported Chinese missile test and the advanced capabilities it demonstrated is the US National Security Council.
“This development is concerning to us as it should be to all who seek peace and stability in the region and beyond,” a spokesperson for the National Security Council told The FT. “This also builds on our concern about many military capabilities that the People’s Republic of China continues to pursue.”
The official also went on to assert that the United States will continue to maintain capabilities needed to "defend and deter against a range of threats” from Beijing.
Other US military officials are also concerned about China's head start in the field of hypersonic weapons, with US Space Force General David Thompson asserting that Washington has "catching up to do very quickly", describing the Chinese missile program as "incredible", but noting that it "greatly complicates the strategic warning problem".
According to the US officials' estimations, China is more advanced in the field than either Russia or the United States.
The Chinese embassy, however, has denied the reports about the alleged missile test, saying that it was "not aware" of it.
“We are not at all interested in having an arms race with other countries,” Liu Pengyu, the embassy spokesperson, told The FT. “The US has in recent years been fabricating excuses like ‘the China threat’ to justify its arms expansion and development of hypersonic weapons.”
The US officials continue to voice concerns that China may step away from its “minimum deterrence” posture that had been maintained for decades, with Washington recently announcing it intends to quadruple its nuclear warheads to as much as 1,000 weapons in the coming decade.