Two sources familiar with the matter told NBC News that the threat cited by Turner, R-Ohio, refers to a space-related capability from the Russian military.

President Joe Biden has been tracking the national security threat and directed White House national security adviser Jake Sullivan to engage congressional leaders, according to two U.S. officials.

White House officials conceded the matter is “serious” but there are ways to “contain” the threat without triggering mass panic, these officials said.

Kind of leaves me curious. Russia has some capability that is space related, and is a threat. Ok. I get the impression this is a newish threat. Or one they recently learned about. And it is "serious".

By stating there are ways to contain the threat without causing "mass panic" one can logically conclude that there are other ways of containing the threat that could trigger mass panic.

They could have not mentioned mass panic at all but, since they did, I can't help but think this is potentially a big deal.

We can speculate but probably won't figure out what's going on without more info and, since it is classified, that's extremely unlikely.

PS: another article

https://abc7news.com/national-security-threat-house-intelligence-committee-mike-turner-jake-sullivan/14424393/

Two sources familiar with deliberations on Capitol Hill said the intelligence has to do with the Russians wanting to put a nuclear weapon into space.

This is not to drop a nuclear weapon onto earth but rather to possibly use against satellites.

PPS: sounds like maybe this has been known about and is a medium to long term issue, not anything immediate.

19.51 CET Mike Johnson declares 'no need for public alarm', reports say

House speaker Mike Johnson has reportedly declared “no need for public alarm” regarding House intelligence committee chair Mike Turner’s national security warning. “Steady hands are at the wheel, we’re working on it, there’s no need for alarm,” Johnson told media on Wednesday afternoon.

His comments come after Turner issued a statement that Congress had been made aware of a “serious national security threat” and called on Joe Biden to “declassify all information” related to it.

During a press briefing, the national security adviser, Jake Sullivan, said he planned to meet with members of the House intelligence committee on Thursday.

“We scheduled a briefing for the for House members of the Gang of Eight tomorrow,” said Sullivan. “I am a bit surprised that Congressman Turner came out publicly today in advance of a meeting on the books for me to go sit with him alongside our intelligence and defense professionals tomorrow.”

Turner’s concerns are reportedly related to Russian military capabilities.