The White House says the weapon is not yet operational and does not pose an immediate threat, but does pose a risk to astronauts.

Russia is developing a space-based anti-satellite weapon that is “concerning” but does not pose an immediate threat, the White House said.

National security spokesman John Kirby said U.S. intelligence officials had information that Russia had developed the technology but that the weapon was not currently operational.

He said U.S. officials were analyzing the information they had and consulting with allies in Europe.

“This is not an active capability that has been deployed, and while Russia’s pursuit of this particular capability is concerning, there is no immediate threat to anyone’s safety,” Kirby said Thursday.

He confirmed that the weapon was a “space-based” weapon, but did not comment on reports in US media that it was either nuclear capable or nuclear powered.

“We are not talking about a weapon that can attack people or cause physical destruction here on Earth,” he said.

Moscow downplayed the US claims, describing them as a “malicious fabrication” that was a ploy by the White House to secure passage of a law billion-dollar Ukrainian aid package by a Republican-led House of Representatives that resists.

“It is obvious that Washington is trying by all means to force Congress to vote on the relief bill,” Kremlin spokesman Dmitry Peskov said in a statement carried by Russian news agencies. “Let’s see what trick the White House will use.”

The US and UK had previously claimed that Russia tested a space weapon in 2020. On this occasion, Moscow said the allegations were “propaganda“.

Kirby said the latest weapon could pose a deadly threat to astronauts in low orbits and potentially disrupt important military and civilian satellites.

It would also violate the 1967 Outer Space Treaty, which prohibits the use of “nuclear weapons or other types of weapons of mass destruction” in orbit or the “stationing of weapons in space by any other means.” More than 130 countries have signed the agreement, including Russia and the USA.

Experts said the US would not be able to counter such a weapon.

US President Joe Biden was kept informed and called for direct diplomatic negotiations with Moscow over the weapon.

The threat came to light after House Intelligence Committee Chairman Mike Turner issued an unusual warning about a “serious national security threat” and called on Biden to “declassify all information related to this threat.”

On Thursday, Andy Ogles, another Republican member of the House of Representatives, called on House Speaker Mike Johnson to examine the possible impact of Turner’s actions on foreign and domestic policy and asked whether he should remain chairman.

White House national security adviser Jake Sullivan also briefed lawmakers.

After the meeting, Turner said Sullivan discussed the government’s options for dealing with the potential threat.

“I think the bottom line is that we all got the very strong impression that the government is taking this matter very seriously and that the government has a plan,” he said. “We look forward to supporting them in their implementation.”

Johnson, who also attended the briefing, said it was “informative” and that the White House would remain in close contact with lawmakers on the matter.

“It is a very serious matter. It concerns Russia,” Johnson told reporters, adding that the administration and Congress would remain in close contact. “And it’s being treated.”

The USA sees Russia and China as its biggest nation-state competitors and says both are developing a range of new weapons systems, including nuclear, cyber and space capabilities.