Dmitry Medvedev, the deputy chairman of Russia's Security Council, issued a stark warning in June.
The undersea cables that enable global communications had become a legitimate target for Russia, he said.
Medvedev's warning came after Nord Stream 2, a pipeline that transfers gas from Russia to Germany, was blown up. Russian officials believed the West had been involved in the attack. (Recent reports suggest Ukraine was actually behind the attack.)
"If we proceed from the proven complicity of Western countries in blowing up the Nord Streams, then we have no constraints - even moral - left to prevent us from destroying the ocean floor cable communications of our enemies," Medvedev posted on Telegram.
Medvedev, a close ally of Russian President Vladimir Putin, has a long history of making incendiary claims.
But some analysts say this wasn't just another idle threat.
A serious warning
The vast network of undersea fiber-optic cables that transfer data between continents is indeed vulnerable to hostile powers, including Russia, the Center for Strategic and International Studies warned in a report this month.
In May, NATO's intelligence chief David Cattler warned that Russia may be planning to target the cables in retribution for the West's support for Ukraine in its war against Russia.
It's a scenario that has NATO's planners increasingly worried.
If the cables are seriously damaged or disabled, swaths of the internet services we take for granted and that our economies rely on, including calls, financial transactions, and streaming, would be wiped out.
Carl-Oskar Bohlin, Sweden's minister for civil defense, said damage to a telecommunications cable running under the Baltic Sea in 2023 was the result of "external force or tampering," though he did not provide details.
And in June, NATO stepped up aircraft patrols off the coast of Ireland amid concerns about Russian submarine activity, The Sunday Times reported.
The threat to GPS
Security analysts say that the internet is not the only network that Russia is probing for vulnerabilities.
In recent months, Russia has been accused of interfering with GPS navigation systems, causing havoc on commercial airline routes. As a result, flights from Helsinki to Tartu, Estonia, ground to a halt for a month in April.
Melanie Garson, an international security expert at University College London, said it was part of Russia's "gray zone" campaign against the West, which involves covert actions that fall below the threshold of open warfare.
"Russia has long been developing this capability and it is currently a cheap and effective way of malicious gray-zone interference," said Garson.
"As we increase our reliance on connectivity and space data in everything from agriculture to food delivery, disrupting national and economic security through interfering with subsea cables and GPS becomes increasingly effective," she added.
Russia puts the West 'on notice'
For decades, the world has depended on data carried by underwater cables that run for thousands of miles. In the early 20th century, the cables carried telegraph signals and later telephone calls.
Robert Dover, a professor of international security at Hull University in the UK, said the cables have long been seen as potential military targets, and both the US and USSR surveilled them during the height of the Cold War.
As the world has become more dependent on the internet, the cables have become increasingly vital. The cables now span around 745,000 miles and are responsible for transmitting 95% of international data.
"The growth in electronic communications has made the undersea cables — vital for international communications, the internet, finance, and so on — a point of vulnerability for nations who use them extensively and for those who don't publicly have an obvious fallback position," Dover said.
Similarly, GPS signals are increasingly vital to the airline industry. They are used to safely guide planes to their destinations and land them.
Planes do have backup navigation systems in the event that GPS fails, but Baltic officials are warning that disrupted GPS signals can still put planes in danger.
During its war with Ukraine, Russia has enhanced its already sophisticated electronic-warfare capabilities, enabling it to remotely scramble the GPS coordinates used to guide missiles and drones.
That's already affected commercial-aviation GPS in Eastern and Northern Europe. Some analysts believe that Russia is sending a signal to the West.
"The targeting of civil-aviation GPS is a means by which to undermine the surety of Western publics in aviation, in particular, and shows the reliance on satellite platforms for ordinary citizens to navigate around," Dover said.
"It also puts governments on notice about the political risks of mass transit accidents that have a plausibly deniable cause."
A backup plan is urgently needed, says expert
Foreign Policy reported in June that NATO has begun taking more action to safeguard undersea cables, setting up a system that would automatically warn of attempted interference.
But Garson said it's not enough, and more government fallback plans are needed in case the systems fail entirely.
"Countries need to not only take measures to protect but also to make sure that the communications system is resilient, e.g., with robust alternatives," Garson said.
She said satellites transmitting GPS data often lack safeguards against attempted interference, while the task of protecting undersea cables often falls on the private companies that own and maintain them.
"It's key to visualize these strategic futures and have a clear resilience plan that accounts for potential systemic risk and to keep countries operational if key comms infrastructure is compromised," Garson said.
In its report this month, the CSIS called for the US to increase international cooperation to coordinate a response to a potential attack on cables.
It said that the current legal and international framework for undersea-cable sabotage was "complex and fragmented, with different international legal regimes determining responsibility and punishment."
"When cables are sabotaged in international waters, there is no regime to hold the perpetrator accountable," it said.