STOCKHOLM — Sweden's biggest submarine hunt since the dying days of the Soviet Union has put countries around the Baltic Sea on edge.
In a scene reminiscent of the Cold War, Swedish naval ships, helicopters and ground troops combed the Stockholm archipelago for a fourth day yesterday for signs of a foreign submarine or smaller underwater craft that officials suspect entered Swedish waters illegally.
While Sweden hasn't linked any country to the suspected intrusion — and Moscow denies involvement — the incident sent a chill through the Baltic Sea region, where Russian forces have been accused of a series of border violations on land, sea and air in recent months.
"Closely following events in the Swedish territorial waters, may become a game changer of the security in the whole Baltic Sea region," Latvian Foreign Minister Edgars Rinkevics wrote on Twitter.
Swedish military officials say there have been three sightings of the elusive craft since Friday. On Sunday they released a photograph taken at a distance of what they said could be the mystery vessel — a dark speck surrounded by foaming water.
Military spokesman Jesper Tengroth said more than 200 personnel were involved in the operation, but stressed that unlike Sweden's submarine hunts in the 1980s, the military wasn't using depth charges or other anti-submarine weapons.
The search made headline news in countries across the Baltic region including in Estonia, Latvia and Lithuania, three former Soviet republics spooked by Russia's intervention in Ukraine.
Estonia stepped up surveillance of its territorial waters, with the border guard looking out for "potential anomalies," spokesman Priit Parkna said.
In Lithuania, the events in Sweden sparked concerns over the safety of a floating natural gas import terminal currently being transported on the Baltic Sea to the Lithuanian port of Klaipeda. The terminal will be key to Lithuania's plans to reduce its reliance on Russian energy.
Meanwhile, Russian media suggested the Swedes were overreacting. The Nezavisimaya Gazeta newspaper even speculated that the submarine hunt could be a ploy staged by the Swedish military to boost its defense 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 the Swedes hadn't found anything.
"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 Defense 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. The unidentified official suggested Sweden should save "taxpayers' money" and ask the Netherlands for an explanation.
The Dutch navy said that the submarine left Sweden on Thursday and had been in Estonia since early Friday. In Sweden, Armed Forces spokesman Philip Simon said the Dutch submarine was not what triggered the Swedish search.
In 1981, a Soviet sub carrying nuclear weapons was stranded off Sweden's southeastern coast, causing an 11-day diplomatic standoff before Swedish authorities allowed the submarine to return home.