The acts bring to mind a notorious market in the Mustamäe district of Tallinn in the 1990s to early 2000s, which often sold pirated CDs and DVDs, AK reported.

One notable wreck is that of a late 16th century merchant vessel of Swedish origin, tentatively referred to as the Nargen.

Maritime archaeologist Ivar Treffner of the national maritime museum (Eesti meremuuseum) said that: "It is clear now that someone had gone and displaced objects there. Pots and ceramics were not in their place, other things had again been moved, while one of the barrels was essentially smashed," he said.

Under Estonian law, recreational divers are permitted to view wrecks, but touching or removing items is prohibited, both the Estonian Maritime Museum and the Heritage Protection Board (Muinsuskaitseamet) say.

Unauthorized diving in areas of objects under heritage protection must be reported, Treffner said, and, depending on the extent of the damage caused, conviction may result in a fine or the loss of the right to dive.

"It hinges on the magnitude of the violation and what has been carried out. There are different options. There is a financial fine, but there is also the option of revoking the permit, heritage board marine archaeologist Maili Roio said.

There are also hazards awaiting illicit wreck divers, including unexploded ammunition and fishing nets, which present the danger of getting intact.

Most of the wrecks in question are in water less than 30 meters deep, and are often of vessels which ran aground, and so remain relatively intact.

Follow ERR News on Facebook and Twitter and never miss an update!