Russia is developing a space-based nuclear weapondesigned to target U.S. satellites, according to three sources familiar with the matter.

The weapon isn’t yet operational, the sources told NBC News, but Moscow’s pursuit of an advanced weapon that could jeopardize America’s vital satellite network has raised concern among U.S. officials, and it prompted the chair of the House Intelligence Committee, Rep. Mike Turner, to issue an extraordinary statementearlier Wednesday calling on the White House to declassify information about an unnamed “serious national security threat.”

Turner, R-Ohio, didn’t provide additional details in his statement. The three sources said he was referring to the Russian effort to field a nuclear weapon in space that could take out satellites that serve as a crucial backbone for U.S. civilian communications, navigation, military operations and intelligence gathering.

Read the rest of the story at NBC News