It is every Alaskan's nightmare: finding themselves within range of a North Korean missile. As that fear came one step closer to reality this week, America's ability to block an incoming attack is under scrutiny.

On Tuesday, the northwestern US state awoke to the news that Pyongyang had test-fired an intercontinental ballistic missile which -- though it came crashing down in the Sea of Japan -- had a probable range of over 5,500 kilometers (3,400 miles), enough to reach Alaskan shores.

The US military has faith that its high-tech defensive systems could fend off any attack from North Korea -- at least for now.

'It's something we have confidence in,' said Pentagon spokesman Navy Captain Jeff Davis, who called the latest development a 'nascent threat.'

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 This graphic shows what the trajectory of the Hwasong-14 intercontinental ballistic missile would be. Some experts say the blast could hit Alaska and parts of Canada 

But other observers are not so sure, rattled by the pace of Kim Jong-Un's missile program and his stated aim of building a nuclear-tipped ICBM.

'Now more than ever, it's imperative for Alaskans and the rest of the nation that we be prepared,' tweeted Senator Dan Sullivan, one of several Alaskan congressmen who backed a bipartisan bill last month aimed at expanding US missile defenses.