Russia is developing a space-based military capability that members of Congress and U.S. officials worry could pose a significant threat to the United States and its allies, possibly by damaging critical intelligence or communications satellites with a nuclear weapon, according to officials familiar with the matter.

The precise nature of the system was unclear. One person referred to it as “a new Russian space threat capability.” Some officials were alarmed after examining classified intelligence on Wednesday and warned of ominous consequences; one member of Congress called it a potential “geo-strategic game changer.” Several lawmakers stressed there was no imminent danger, but they urged the Biden administration to take countermeasures soon.

The Russian government has experimented with the use of nuclear explosions or directed energy to disable satellites, according to one U.S. official, who, like others, spoke on the condition of anonymity to discuss sensitive information. Experts have raised concerns that a nation could detonate a nuclear weapon in space to interfere with satellites through the emission of radiation.

Russia also has tested anti-satellite weapons. In 2021, after it launched a missile from Earth that destroyed a Soviet-era satellite, a senior U.S. military official warned that Russia was “deploying capabilities to actively deny access to and use of space by the United States and its allies.”

A day of fevered speculation about what the supposed space-weapon might be was triggered by an unusual and cryptic public statement Wednesday by a leading member of Congress, who urged lawmakers to review classified information about what he called a “serious national security threat.”

Rep. Michael R. Turner, R-Ohio, chairman of the House Intelligence Committee, did not specify the nature of the threat or the country supposedly wielding it.

In a separate letter to fellow House members, Turner and Rep. Jim Himes of Connecticut, the committee’s top Democrat, said the committee “has identified an urgent matter with regard to a destabilizing foreign military capability that should be known by all congressional policymakers.”

The lawmakers said the full committee voted on Tuesday to make the intelligence available to all House members for their in-person review in a secure room at the Capitol.

The information was obtained using authorities granted to the intelligence community under Section 702 of a key electronic surveillance law that is being hotly debated in Congress, according to officials with knowledge of the matter.

Turner, a strong proponent of the surveillance authority, appears to want to use the information about the adversary capability to convince skeptical colleagues that 702 is an indispensable intelligence tool, one official said.

Himes cautioned that the information Turner highlighted doesn’t concern a “panic now” issue. “It is a serious national security issue in the medium-to-long term that the Congress and the administration need to focus on,” Himes said. “But no need to buy gold.”

House Speaker Mike Johnson, R-La., also urged caution. “I want to assure the American people there is no need for public alarm. We are going to work together to address this matter, as we do all sensitive matters that are classified,” he told reporters.

One Capitol Hill aide expressed annoyance at Turner for alerting the public about the information ahead of a planned briefing for top House lawmakers in the “Gang of Eight,” who are traditionally privy to some of the most sensitive intelligence information.

Lawmakers in the House and Senate have been in possession of the raw intelligence concerning the foreign capability for several weeks and were preparing to learn how the administration might respond, this aide said. Turner’s disclosure could make that response more difficult if it revealed information about how the intelligence was obtained in the first place, the aide said.

Turner, in his initial statement, called on the Biden administration to declassify all information about the threat.

President Joe Biden was made aware of the threat earlier and directed national security adviser Jake Sullivan to offer a briefing to senior lawmakers last week. “It is highly unusual, in fact, for the national security adviser to do that,” Sullivan told reporters at the White House. He questioned why Turner chose to make the matter public, considering that Sullivan plans to meet with members on the Hill on Thursday, along with intelligence and defense personnel.

That meeting, he said, “has been on the books” for Thursday. “So I am a bit surprised that Congressman Turner came out publicly today in advance of the meeting … for me to go sit with him alongside our intelligence and defense professionals tomorrow. That’s his choice to do that,” Sullivan said.

Asked if the meeting he requested was to discuss the same “serious national security threat” that Turner referred to in his statement, Sullivan demurred. “I’ll leave it to you to draw whatever connections you want,” he said. “I’m not in position to say anything further from this podium at this time.”

Sullivan added that the Biden administration “has gone further, and in more creative, more strategic ways,” to declassify intelligence “in the national interest of the United States than any administration in history.” But “at the same time, we, of course, have to continue to prioritize and focus very much on the issue of sources and methods.”

The Washington Post’s Karen DeYoung, Abigail Hauslohner and Marianna Sotomayor contributed to this report.

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