The Democratic People's Republic of Korea (DPRK) said Wednesday that it was natural for it to bolster missile capability to strike the stronghold of U.S. aggression, the official KCNA news agency reported.
The DPRK had strategic rocket forces that could bring the U.S. mainland and other military bases within range, the foreign ministry was quoted as saying.
An unnamed spokesman also denounced the U.S. as the primary cause of a new missile arms race in Northeast Asia, which opened the way for South Korea to develop missiles capable of launching a preemptive attack on its northern neighbor.
"The U.S threw cold water over the effort for stability of the Korean Peninsula and its surrounding areas, and destroyed the foundation for dialogue and negotiations," the spokesman said.
Pyongyang's announcement followed a presidential statement from South Korea on Sunday, which said it planned to develop ballistic missiles with a range of 800 km -- compared with a previous limit of 300 km -- under a revised pact with the United States.
The new range could cover the entire peninsula and enable Seoul to better respond to perceived missile threats from the DPRK.
Critics say South Korea's extension plan contradicts its commitment to a global arms control agreement, the Missile Technology Control Regime (MTCR), which aims to curb the spread of missiles and unmanned aerial vehicles that could deliver weapons of mass destruction.
The White House on Sunday defended South Korea's pursuit of longer-range missiles as "absolutely legitimate to respond to a threat posed by the DPRK's ballistic missile program."