Canadian Prime Minister Mark Carney stressed the importance of working with NATO allies to defend against growing threats in the melting Arctic as he chose a German-Norwegian offer to build a new fleet of submarines for Canada’s navy.

Thyssenkrupp Marine Systems is the preferred supplier to build as many as 12 submarines, Carney said in a speech at a naval base in Halifax, Nova Scotia, where he stopped en route to the NATO summit in Ankara.

The German firm beat out South Korea’s Hanwha in what the prime minister said was a close competition.