Shipping firms may need to pay a fee to use the Baltic Sea, one of the world's busiest shipping routes, in order to cover the high costs of protecting undersea cables, Estonia's defence minister said on Wednesday following a spate of breaches.

Sweden said Sunday that it seized a vessel suspected of damaging a fiber-optic cable under the Baltic Sea that links the country to Latvia, in what authorities are investigating as an act of "aggravated sabotage.

The Stockholm prosecutor's office announced on Sunday evening the initiation of an investigation into a possible sabotage in the Baltic Sea and the seizure of a ship suspected of damaging an underwater cable between Sweden and Latvia.

Sweden is investigating damage to a data cable linked to Latvia, the latest breach in the Baltic Sea region where European authorities are on high alert.

Swedish authorities boarded a vessel suspected of being involved in an earlier underwater sabotage of cables in the Baltic Sea on Monday.

Sweden has opened a preliminary investigation into suspected aggravated “sabotage” and ordered the detention of a vessel in the Baltic Sea suspected of damaging an underwater fiber optic cable connect

The undersea cable is based in the Baltic Sea, and may have been deliberately damaged on Sunday, according to officials in Sweden.

By Johan Ahlander and Anna Ringstrom STOCKHOLM (Reuters) -Swedish authorities boarded a Maltese-flagged ship seized in connection with the latest breach of cables running along the bottom of the Baltic Sea to begin an investigation into the matter,

Several undersea cables running under the surface of the Baltic Sea have been damaged in suspected sabotage incidents in recent months.