STOCKHOLM (Reuters) - Finland's telecoms operator said on Monday that the damage reported last week to its C-Lion1 telecoms cable in the Baltic Sea may have occurred as early as January 26, the same day a cargo ship broke another undersea cable in the area.

Swedish and Finnish police said on Friday they were investigating a suspected case of sabotage of the C-Lion1 cable running along the seabed from Finland to Germany, while adding it was not immediately clear when the damage had occurred.

The Baltic Sea region is on alert and the NATO alliance has boosted its presence after a series of power cable, telecom and gas pipeline outages since Russia invaded Ukraine in 2022. Most have been caused by civilian ships dragging their anchors.

Operator Cinia said in an emailed statement on Monday that it believed the damage of the C-Lion1 had occurred on January 26 at 0237 a.m. Finnish time (0037 GMT) and that the cause was still unknown.

The time closely coincides with that of an outage of a nearby subsea fibre optic cable linking Sweden and Latvia, which was reported at the time.

A Swedish prosecutor said on February 3 he had concluded that a Maltese-flagged bulk carrier, the Vezhen, had ruptured the cable linking Sweden and Latvia with its anchor, but that it had been an accident and not sabotage.

The Vezhen passed the Sweden-Latvia cable at 0045 GMT on January 26, MarineTraffic data analysed by Reuters showed.

Swedish police did not immediately respond to a request for comment when contacted by Reuters on Monday.

Bulgarian shipping company Navigation Maritime Bulgare, which lists the Vezhen among its fleet, also did not immediately respond to a request for comment on Monday.