Sweden's government said yesterday it would boost defence spending significantly over the next decade if re-elected, in response to a growing threat from Russia.

The centre-right government, trailing in polls ahead of a national election in September, said it planned to gradually increase spending up to 2024, buying more fighter jets and submarines and boosting its military presence in the Baltic Sea.

"In the budget for 2015 we will propose a significant strengthening of the military," the leaders of the four parties in the Alliance government said in a signed article in Dagens Nyheter.

Sweden has been running down its military since the end of the Cold War, and the Alliance said it became aware of an increasing threat from Russia in 2009.

"What we are seeing now is Russia's actions confirm and exceed the fears we had then," it added in a clear reference to Ukraine, where Moscow's annexation of Crimea has triggered the worst crisis in relations with the West since the fall of Communism.

The Alliance plans for the annual increase in spending to reach 5.5 billion crowns ($832 million) by 2024.