According to the paper, the submarine-hunting corvette HMS Malmö was secretly deployed to comb the waters between Lidingö and Nacka, about two miles (3 kilometres) from Stockholm's city centre and close to busy ferry lanes, after a suspected sighting on October 31st.
This was just a week after Swedish armed forces called off the search for the suspected submarine first reported on October 16th.
“It look like a black submarine conning tower,” DN’s source said, describing the photo of the second sub. “You can also see several over vessels which normally travel along the shipping channel, such as the Finland ferries.”
"You don't go this far in towards Stockholm for the fun of it. This information points to a serious intrusion towards central Stockholm."
According to the source, photographs taken of the suspected submarine are clearer and more detailed than those that caused a sensation earlier in the month. The paper, however, did not publish any new photos in its report.
Philip Simon, head of press for the Swedish Armed Forces, confirmed that a second submarine sighting had been registered.
“The information in Dagens Nyheter is correct,” he told TT. “This event is classified as a possible submarine. That we opted to investigate further reflects both the credibility of the person who made the sighting and the fact that we had both vessels and ground forces in the vicinity, which meant we could rapidly reach the site. Despite that, we got no result.”
Simon added that Sweden’s defence forces had received more than 400 reports of submarine sightings, after the military reported three separate sightings.
In November the Swedish military released images of tracks on the sea bed and an apparent submarine periscope which it said proved that "a mini submarine violated Swedish territory" between October 17 and October 24 and that "at least one vessel" was involved.
The week-long search after the previous sighting involved battleships, minesweepers, helicopters and more than 200 troops scouring an area 30 to 60 kilometres (20 to 40 miles) from the capital. It stirred up memories of Cold War cat-and-mouse games. However, despite widespread speculation that the submarine was Russian, the military never identified its nationality.
According to a poll released on Sunday by the Swedish Civil Contingencies agency, Swedish concern about Russia has risen sharply following the sightings, with 73 percent of Swedes expressing worries about developments in the country in 2014, up from 45 percent in 2013.
For the first time the annual poll found more Swedes were in favour of Nato membership (48 percent) than were opposed (35 percent).