Leader Kim Jong-un supervised Sunday's test of the missile, called "Pulhwasal-3-31".
The missile is identical to the strategic cruise missiles the North said on Wednesday were under development.
KCNA said the missiles flew above the sea off the country's east coast for 7421 seconds and 7445 seconds and hit an unspecified island target, indicating the flight time exceeded two hours.
Kim called the test a success, KCNA said, "which is of strategic significance in carrying out the plan ... for modernising the army which aims at building a powerful naval force".
South Korea's military said on Sunday the North fired multiple cruise missiles off its coast but did not provide details.
North Korea's ballistic missiles are typically more controversial and are explicitly banned under United Nations Security Council resolutions.
But analysts have said intermediate-range cruise missiles are no less a threat than ballistic missiles and are a serious capability for North Korea.
In recent months, the North has tested an array of weapons that include ballistic missile systems that are under development and an underwater drone.
Kim separately inspected the construction of a nuclear submarine and discussed issues related to the manufacturing of other types of new warships, KCNA said.
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