Sweden says it has proof that a foreign military submarine did illegally enter its waters last month, sparking a huge search.
It does not know which country was responsible but is warning against any further intrusions.
Its evidence includes a sonar image of tracks on the sea floor and a picture showing a bubble pattern typical of a diving submarine.
Prime Minister Stefan Lofven said intrusion into Swedish territorial waters was unacceptable and that Sweden would bolster its capabilities in detecting and identifying such activity.
“Anyone considering approaching Swedish territory in an unauthorised way should be aware of the enormous risks that those directly involved could face for such a violation…We will defend our territorial integrity with all means available,” he told a news conference.
The mysterious episode triggered “Sweden’s biggest military mobilisation since the Cold War”.:http://www.euronews.com/2014/10/18/sweden-steps-up-search-for-foreign-submarine/
Amid rising tensions between Europe and Russia over the crisis in Ukraine, speculation centred on suspicions that Moscow had sent the vessel, something it strongly denied.
Sweden has already said it will increase spending on its military, including up to 70 new fighter jets and new submarines, as it looks to reverse decades of underspending on its armed forces.
The Nordic country has also drawn closer to NATO in the past few years although the current government has ruled out seeking membership of the US-led alliance.