The New York Times reports that US defense and intelligence officials have been expressing increased concern about the "aggressive" activities by the Russian Navy's submarine and spy ship fleet in the proximity of critical undersea communications cables, perhaps assessing them for potential attack in the event of a crisis. There's no evidence that the Russians (or anyone else) have cut cables yet, but the intelligence agencies of the US and its allies have observed increased activity by the Russian fleet along cable routes, even close to the United States.

The US has long been known to have tapped undersea cables for intelligence collection. One early example is a US program in the 1970s called Operation Ivy Bells, which attached a listening device to Soviet communications cables in the Sea of Okhostsk linking facilities in the Kuril Island chain, recording unencrypted communications on tapes that were retrieved by divers monthly. The program ended in 1981 after a National Security Agency employee sold information about the program to the Soviets for $35,000.

While no US Navy or intelligence officials would go on the record regarding their concerns, the Navy's Commander of US Naval Forces Europe and US Naval Forces Africa, Admiral Mark Furguson, noted that Russian submarine patrols have risen in number by nearly 50 percent in the last year. Unnamed military and intelligence officials told the Times that much of the activity is happening along cable routes. A European diplomat, unnamed by NYT, was quoted as saying, "“The level of activity is comparable to what we saw in the Cold War.”

In September, the Russian Navy's oceanographic research ship Yantar, carrying unmanned underwater surveillance vehicles, was observed operating near the US Navy base at Guantanamo Bay, Cuba, and elsewhere in the Caribbean. According to reports, it was believed to be surveying Caribbean undersea cable networks. The US operates similar ships, including the USNS Impeccable (T-AGOS-23), which conduct underwater "surveys" with devices such as the Surveillance Towed Array Sensor System (SURTASS). One of those surveys happened in the South China Sea in 2009 and led to a confrontation with Chinese naval vessels.

While cable breaks happen all the time because of seismic activity or even shark attacks, a concerted effort to cut multiple undersea cables could cause disruption of the global Internet and have both economic and military repercussions. Despite its network of communications satellites, the US military is heavily dependent on undersea cables for much of its communications.

While it's possible that the Russians could simply be looking for locations where submarines can deploy gear and possibly divers to tap into communications cables for surveillance purposes, officials told the Times it is more likely that they were looking for hard-to-reach locations to cut cables during future operations. Such locations would make it difficult and time-consuming to repair cables, maximizing the impact of cuts.