Observers doubt the new US president will buy the world's largest island but his interest underlines its strategic importance President Donald Trump's claim that US ownership and control of Greenland is "an absolute necessity" has underlined the strategic importance of the world's largest island in terms of American missile defences and anti-submarine operations.

U.S. President-elect Donald Trump is once again making waves with his pursuit of Greenland, this time refusing to rule out using force to gain control of the Arctic island from ally Denmark. But Washington had been interested in Greenland long before Trump came along.