The press conference was held in Berga on a rainy and grey day by the water.
The communications director of the Armed Forces, Erik Lagersten, told reporters that "the operation was going into a new phase".
When pressed to explain what he meant, Lagersten was extremely delicate with his choice of words, saying that the hunt was so far being carried out "according to plan".
Many journalists were left baffled after the mysterious "new phase". Photo: TT
He refused to confirm or deny a series of questions from journalists on the scene.
"I cannot comment on an ongoing operation," he repeated.
Johanne Hildebrandt, a fellow at The Royal Swedish Academy of War Sciences, told The Local that the choice of words suggested the Armed Forces were toning down operations.
The search has reached the sixth day. Photo: TT
Search teams resumed their large-scale hunt for the suspected submarine on Wednesday morning after spending the night watching and listening to other ships and vessels in the area.
A few hours ahead of the briefing, officer Dag Enander told news agency TT that there were no plans to downsize the operation in the Baltic Sea:
"We are moving forward with the same scale and orientation. We'll drive on as before, business as usual".
Battleships, minesweepers, helicopters and more than 200 troops have been scouring an area about 30 to 60 kilometres from the Swedish capital after a "man-made" object was spotted.
But some defence experts have cast doubt on the chances of a quick discovery.
Jörgen Elfving, a former lieutenant colonel and military expert, told Swedish network SVT:
"This is an operation that takes time. It needs patience".
He added: "What is going on is like looking for a needle in a haystack".
But Deputy Operation Commander Anders Grenstad insisted that the Swedish military had time on its side.
"We can keep going for a long while if we so desire," he told SVT.