Sharpening his rhetoric on Greenland, US President Donald Trump raised questions about NATO's reliability, signalling that security commitments to Europe could increasingly be tied to economic and strategic leverage. At a White House news conference marking one year since his return to office, Trump declined to say how far Washington might go to secure US interests related to Greenland. Asked directly, he replied: "You'll find out." Pressed on whether force was an option, Trump avoided specifics. He pointed instead to economic tools. He said tariffs, licensing and "other alternatives" were available and described them as "the best, the strongest, the fastest."