Sweden hunts for mystery submarine

The Swedish military on Monday intensified a search in the ocean off Stockholm for an underwater mystery vessel, but stopped short of calling it a submarine. Civilian vessels were ordered to stay at least six miles (about 10 kilometers) away from the Swedish warship conducting the search, the English-language website The Local reported, according to CNN.

The search began Thursday after Swedish intelligence picked up an emergency radio call in Russian, reported The Local, citing the Swedish newspaper Svenska Dagbladet.

The radio transmissions were being sent to the Russian enclave of Kaliningrad, 330 miles (530 kilometers) south of Stockholm on the Baltic's southern shore, according to The Local report.

There were also reports that a foreign vessel was spotted in the waters near Stockholm.

Russia on Sunday denied it has any vessel in Swedish waters. Moscow suggested the vessel may belong to the Netherlands and have been involved in naval exercises off Sweden, according to a report from Russia's Itar-TASS news agency.

The Dutch were quick to respond, saying a sub involved in the exercises was anchored in Tallinn harbor of NATO-ally Estonia for the weekend, according to a report from Agence France-Presse.

On Monday, the Swedish military vowed to continue searching at least for the next few days, according to The Local.