North Korea says it has long-range missiles capable of reaching as far as the United States mainland.
The statement on Tuesday comes two days after South Korea announced that it would almost triple the range of its ballistic missile system, following a new agreement with the US.
Under the previous security deal, it had been restricted to missiles with a range of 300km. The new deal extends that range to 800km.
The North Korean statement says US bases in "Japan, Guam and the US mainland" were within its "scope of strike".
Pyongyang is thought to be working on a long-range missile, but two recent rocket tests ended in failure, the BBC reports.
North Korea's neighbours said the failed launches - in April 2009 and April 2012 - were tests related to the development of the long-range Taepodong-2 missile system.
The system, which analysts believe is intended to put the US mainland within striking range, has not yet been tested successfully.
North Korea routinely issues strong rhetoric against Seoul and Washington. But the Communist state does possess an array of short- and medium-range missiles, as well as artillery pointed towards South Korea.
The statement, carried by state-run KCNA news agency and attributed to North Korea's National Defence Commission, said Pyongyang would match any enemy "nuclear for nuclear, missile for missile".
It added that the missile deal between the US and South Korea was "another conspiracy of the master and the stooge to push the situation on the Korean Peninsula to the extreme... and ignite a war".
The two Koreas remain technically at war following the 1950-53 Korean War, which ended in an armistice.
The US has more than 28,000 troops in South Korea and provides security guarantees for its ally.
