Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, called China’s recent test of a hypersonic weapons system “very concerning” — and “very close” to a Sputnik moment as Beijing rapidly expands its military capabilities.

Milley, the United States’ top military officer, is the first U.S. official to acknowledge the provocation publicly, telling Bloomberg Television in an interview aired Wednesday that “what we saw was a very significant event.”

China’s test of the hypersonic system coincides with its broader effort to enhance strategic and nuclear weapons capabilities, developments being closely watched in Washington. Though military leaders have been reluctant to comment on the hypersonic system, the swift pace of China’s advancement — including its construction of new missile silos and new ballistic missile submarines — has alarmed U.S. officials.

“There’s a suite of issues with respect to China … that deeply concern us,” Pentagon spokesman John Kirby said later Wednesday. “They’re informing the budget. They’re informing the programs and the priorities of the department, they’re going to inform in many ways our training and exercise regimen. So there’s a lot here.”

As The Washington Post reported last week, a test conducted in August involved a nuclear-capable hypersonic vehicle that partially orbited the globe before hurtling to Earth. The demonstration analysts said, was less noteworthy for the technology, which China’s military has been developing for years, than for the fact that Beijing decided to test it. Some likened it the Soviet Union’s 1957 launch of a satellite called Sputnik that provided an early edge in the space race.

Milley, noting that the term “Sputnik moment” had been used in some news reports since the test, stopped short of that assessment in his interview with Bloomberg. “I don’t know if it’s quite a Sputnik moment, but I think it’s very close to that,” he said, adding, “It has all of our attention.”

Milley noted that the United States also is “experimenting, and testing and developing technologies to include hypersonics, artificial intelligence, robotics — a whole wide range.”

Kirby, speaking during a routine news briefing at the Pentagon, would not detail how far along the United States is in its development of such systems, except to say “our own pursuit of hypersonic capabilities is real, it’s tangible and we are absolutely working toward being able to develop that capability.”

“It’s not a technology that is alien to us,” he added. “And I would argue that it’s not just our own pursuit of this sort of technology, but our mindfulness that we have defensive capabilities too that we need to continue to hone and improve.”

Both Kirby and Milley stressed that the test reflects just one weapon system on Beijing’s side, with the general acknowledging China’s capabilities “are much greater than that.” Referring to its growing capacities in space, cyberspace and traditional domains of land, sea and air, he said, “They’re expanding rapidly.”

“We’re in one of the most significant changes in what I call the ‘character of war,’ ” Milley said. “We’re going to have to adjust our military going forward.”

China’s test is a reminder that Beijing has become what Defense Secretary Lloyd Austin frequently calls the United States’ “pacing challenge” militarily — and of the lack of consensus over how Washington should respond.

China has been secretive about its weapons testing — in fact, on Oct. 18, it denied even conducting a hypersonic test. A spokesman for Beijing’s foreign ministry argued that China merely had tested “regular spacecraft” intended for “peaceful uses of outer space.”

Some experts fear the prospect of entering a new arms race with Beijing, citing the dangers of a contest between two nuclear powers. President Biden is said to be weighing adopting a “no first use” nuclear posture, as a means of reducing tension. In September, he said at the United Nations that while the United States was prepared to check Beijing’s military and economic ambitions, “we do not want a new Cold War.”

The administration has yet to announce a specific policy regarding its approach toward an increasingly militarized China.

Ellen Nakashima contributed to this report.