Sweden has confirmed an embarrassing fact: that its defense forces have been hunting minks, not Russian submarines.

"It's a sad fact that what was originally stated to be intrusions into our waters have proved to be minks," Prime Minister Ingvar Carlsson said Friday.

For the last 20 years, Sweden has often protested loudly and internationally that foreign submarines -- principally from the former Soviet Union -- were sneaking around its long coastline.

But Owe Wiktorin, the armed forces Chief of Staff, revealed a discovery as he presented a report about military and naval activity. He said that although security equipment had long detected sounds that the country had identified as coming from submarines, hydrophonic instruments introduced to the Swedish Navy in 1992 had shown that minks could give off sound patterns similar to those of submarines.