SEOUL—North Korea threatened to turn the U.S. into “huge heaps of ashes” and warned that military exercises involving American and South Korean forces this week had worsened the standoff, which could only be resolved by “absolute force.”

In a strongly worded commentary issued through its state media on Tuesday, Pyongyang attacked President Donald Trump, branding his approach to the crisis on the Korean Peninsula “unimaginably reckless.”

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