(CNN) Russia attempting to develop nuclear space weapon to destroy satellites with massive energy wave, sources familiar with intel say. Quoting,

Russia is trying to develop a nuclear space weapon that would destroy satellites by creating a massive energy wave when detonated, potentially crippling a vast swath of the commercial and government satellites…

See (Wikipedia) Starfish Prime, a 1962 high altitude nuclear test, detonated at an altitude of 250 miles. Quoting,

Starfish Prime caused an electromagnetic pulse (EMP) that was far larger than expected, so much larger that it drove much of the instrumentation off scale…

The weaponeers became quite worried when three satellites in low Earth orbit were disabled. These included TRAAC and Transit 4B.[13

Starfish Prime created  artificial  Van Allen radiation belts :

…In the months that followed, these man-made radiation belts eventually caused six or more satellites to fail,[14] as radiation damaged their solar arrays or electronics, including the first commercial relay communication satellite, Telstar, as well as the United Kingdom’s first satellite, Ariel 1.[15] Detectors on Telstar, TRAAC, Injun, and Ariel 1 were used to measure distribution of the radiation produced by the tests.

In 1963, it was reported that Starfish Prime had created a belt of MeV electrons.[17] In 1968, it was reported that some Starfish electrons had remained in the atmosphere for 5 years.[18]

(CNN) House Intel Chairman announces ‘serious national security threat,’ sources say it is related to Russia. Quoting,

One of the sources who has seen the intelligence confirmed that “it is, in fact, a highly concerning and destabilizing” Russian capability “that we were recently made aware of.”

Sensitivity has two  possible roots:

• The need to protect sources and methods.
• Disclosure would affect society at large in a negative way.

“Destabilizing” hints the latter. One of my long-term concerns has been North Korea’s Plutonium, Iran’s Uranium / Suitcase Nukes,

where Russia may have obtained or retained custody of refurbished weapons, with possible deployment in the continental U.S.