Damage to two undersea fiber-optic cables in the Baltic Sea this month points to growing vulnerability of critical submarine infrastructure, with German officials suspecting sabotage and Swedish police investigating a Chinese cargo vessel’s involvement.

The incident highlights escalating risks to the global submarine cable network, which carries 99% of international telecommunications traffic through 530 cable systems spanning 850,000 miles. These garden hose-thick cables facilitate trillions in daily financial transactions and vital government communications.

Security experts warn that Russia has increased monitoring of undersea cables amid tensions over Ukraine. Taiwan reported 36 cable damages by foreign vessels since 2019, while Houthi rebels denied targeting Red Sea cables this year. Though most of the 100-plus annual cable faults are accidental, deliberate sabotage remains a concern. Repairs are costly, with new transatlantic cables running up to $250 million.