REUTERS/Peter Dejong/Pool
"This is uncharted territory," the official added.
The Journal reports that U.S. officials don't know how Russia hid its military plans from the National Security Agency, which spies on digital and electronic communications.
Russian leaders either "deliberately avoided communicating about the invasion or simply found a way to do so without detection by the U.S.," The Journal notes.
It's also unclear if the Kremlin's new camouflage it is part of a larger trend that could impact America's ability to deter Russia.
"All military combat operations depend on NSA contributions," Robert Caruso, a former assistant command security manager in the Navy and a consultant, told Business Insider in regards to documents potentially accessed by Edward Snowden. "[The Department of
Some officials doubt that the U.S. could have done much differently as Russian special forces began a slow takeover of the strategic Black Sea peninsula, but the inability to see the developments has them concerned nonetheless.
U.S. spy agencies and the military are now implementing a "surge" of assets to expand satellite coverage and communications-interception in the region, the Journal reports.