Russian media has claimed Sweden is overreacting. The Nezavisimaya Gazeta newspaper suggested the submarine hunt could be a ploy staged by the Swedish military to boost its defence budget, which has undergone a series of cuts since the Cold War.
The official government newspaper Rossiiskaya Gazeta questioned whether there was any submarine at all, noting nothing had been found by Sweden.
"Either Sweden's echo location equipment is working badly or, as the old saying goes, the eyes of fear see danger everywhere," the paper said.
A defence ministry official quoted by the Tass news agency pointed fingers at a Dutch submarine that participated in an exercise with the Swedish navy last week.