Russian spy ships are 'aggressively operating' near critical undersea internet cables. America is worried.

A Russian nuclear submarine — (Image credit: FRED TANNEAU/AFP/Getty Images)

Almost all global internet communications travel through a network of undersea cables. If those cables were to be cut, it would serve a devastating blow to Western governments, citizens, and the estimated $10 trillion worth of global business carried daily by the cables. The idea of such an attack has the U.S. worried, as The New York Times reports that Russian submarines and spy ships are "aggressively operating" near the vital undersea cables.

Though Russia hasn't actually cut any cables, one commander of a Navy submarine fleet told The New York Times that he's "worried every day about what the Russians may be doing." Just last month, one Russian ship with two deep-sea submersible craft was spotted slowly sailing by the location of one major cable.

"The level of activity is comparable to what we saw in the Cold War," a senior European diplomat told the Times.