Mr Austin made the remarks in Seoul on Thursday following annual security talks with his South Korean counterpart. The talks largely focused on challenges from China and North Korea.
He vowed that the US would “maintain its capability to defend and deter” potential threats posed by China.
Beijing’s military aggression and its drive to counter American influence in Asia have been a cause of concern for Washington. Relations between the US and China remain troubled over the issue of Taiwan, which Joe Biden has said he would defend in the event of Chinese military action.
According to experts, the weapons system is clearly designed with the purpose of evading US missile defences.
Hypersonic weapons fly at five times the speed of sound offering stealth and manoeuvrability, which could potentially pose crucial challenges to missile defence systems.
“We have concerns about the military capabilities that the PRC [People’s Republic of China] continues to pursue, and the pursuit of those capabilities increases tensions in the region,” Mr Austin said.
Referring to Beijing’s advances in the realm of military capabilities which could pose a threat to Washington, Mr Austin added that “it just underscores why we consider the PRC to be our pacing challenge.”
The Xi Jinping government, however, has denied that the test involved a weapon, suggesting instead that it was a “space vehicle”.
The hypersonic arms race has escalated among the US, Russia, China and North Korea after the nuclear-capable countries announced or initiated various tests of hypersonic weapons through this year.
Mr Austin said he and South Korean defence minister Suh Wook discussed a wide range of topics pertaining to North Korea. The two agreed that North Korea’s advancement of its missile and other weapons programmes “is increasingly destabilising for regional security".
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