A data cable linking Germany and Finland along the seabed has been broken and may have been cut off by an outside force, according to the Finnish state-owned cyber security and telecoms network firm Cinia.
The 1,200 km (745 miles) C-Lion1 cable running through the Baltic Sea from Finland's capital Helsinki to the German port of Rostock malfunctioned just after 0200 GMT, the company said.
The sudden outage implied that the cable was completely severed by an outside force, although a physical inspection has not yet been conducted, Cinia's Chief Executive Ari-Jussi Knaapila told a news conference.
The damage occurred near the southern tip of Sweden's Oland island and could typically take between five and 15 days to repair, he added.
Cinia said it was working with authorities to investigate the incident.
Last year a subsea gas pipeline and several telecoms cables running along the bottom of the Baltic Sea were severely damaged in an incident raising alarm bells in the region.
Finnish police investigating the 2023 case have named a Chinese container ship believed to have dragged its anchor as a prime suspect, but have not said whether the damage was believed to be accidental or done with intention.
In 2022 the Nord Stream gas pipelines linking Russia to Germany in the Baltic Sea were destroyed by explosions in a case that remains under investigation by German authorities.
