Authorities said Wednesday they were investigating the deaths of some 60 seals, both adults and stillborn pups, found on the coast of a Anholt, a Danish island midway between Denmark and Sweden.

The island is a sanctuary for roughly 250 seals - part of the estimated 10,000 common seals that live in Kattegat, the Baltic Sea waterway between the two Scandinavian countries.

Autopsies indicated «they likely died of a bacteria infection in their respiratory system,» said Per Leth Soerensen, of the government Danish Forest and Nature Agency. More tests will be carried out to identify the bacteria, he said.

The corpses have been found on the southern sandy beaches of Anholt, a scarcely populated island some 150 kilometers (90 miles) northwest of the capital, Copenhagen, Leth Soerensen said.

Leth Soerensen said the agency would contact its counterparts in other countries surrounding the Baltic Sea to find out whether they have received similar reports.

"There are probably more dead animals out there that eventually will wash up on nearby shores," he said.

In 1988, several hundreds seals in the North Sea died after suffering a pneumonia that had been caused by virus, but Leth Soerensen said he did not think the situations were related.

"Our first guess is that it has nothing to the 1988 deaths," he said.