The U.S. has acknowledged for the first time that it has an operational weapon in Earth’s orbit, prompting China to warn against an “arms race” in space.

The United States has confirmed it deployed a space weapon in Earth’s orbit, marking the first time it has acknowledged such offensive capabilities, according to the BBC.

U.S. Secretary of the Air Force Troy Meink said the “on orbit” weapon was necessary to safeguard U.S. forces against hostile enemy action. Speaking at the Air, Space and Cyber Conference on Monday, Meink said the U.S. was ready for “evolving threats,” but did not elaborate on the weapon’s capabilities or when it was put into orbit.

Senior military leaders have previously said they planned to boost military capabilities in space, citing Russian and Chinese programmes developing ways to attack and disrupt U.S. satellites in a future conflict.

China responded on Tuesday by warning against an “arms race” in space. “We urge the US side to stop expanding its military capabilities and preparing for war in outer space,” AFP quoted a foreign ministry spokesman as saying.

Details of how the weapon operates have not been disclosed by U.S. officials. A U.S. Space Force spokesperson said: “Space control encapsulates the mission areas required to contest and control the space domain – employing kinetic and non-kinetic means to affect adversary capabilities through disruption, degradation and even destruction, if necessary.”

“These capabilities can be employed for offensive and defensive purposes at the direction of combatant commands.”

An expert on military uses of outer space noted that “precious little” was publicly known about the technology, and told the BBC there could be a “whole range of different weapons systems.”

Speaking to Radio 4’s Today programme, Dr Bleddyn Bowen, from the Royal United Services Institute (RUSI), said he was “totally guessing” but that the U.S. could have been referring to “some kind electronic warfare or radio jamming platform.” That would be the sort of weapon that already exists on Earth and could disrupt radio communications, Bowen said.

An alternative would be “a kinetic kill vehicle of some sort – so a vehicle that would release a projectile of some sort that would ram into a satellite and destroy it.” But this was less likely because such a physically destructive tool would be capable of creating a lot of debris, Bowen added.

The Trump administration has said that space-based capabilities – and interceptor missiles – are a crucial part of its planned “Golden Dome” defence system to protect the U.S. from missiles and other airborne threats. Last year President Donald Trump issued an executive order underlining the U.S. Space Force’s role in not only defending assets, but also as an attacking force.

The U.S. Space Force – the first new branch of the U.S. military for more than 70 years – was launched in 2019 as a way to protect American assets in space, including hundreds of satellites used for communication and surveillance.

A 1967 treaty banned weapons of mass destruction in orbit. Since then, key powers including the U.S., Russia, and China have been exploring other capabilities outside of the treaty, such as targeting rivals’ satellites – which are key for military communications, surveillance and navigation.

In early February, it was revealed that two Russian satellites had likely intercepted the communications of at least a dozen European ones since Russia’s invasion of Ukraine in 2022. Such interceptions may have allowed Russian intelligence services to read the sensitive data they transmit, or hypothetically, even to take control of the satellites.

In 2024, the U.S. said Russia had launched a satellite which it believed may be capable of attacking other such probes. Russia did not publicly comment on the issue.

The U.S. Space Force says China “develops and operates space and counterspace capabilities as part of a military modernisation strategy,” while Russia “views space as a warfighting domain and believes space supremacy will be a decisive factor in future conflicts.”