North Korea's apparently successful test-firing Sunday of a new intermediate-range ballistic missile points to a significant advance in the reclusive nation's goal of mastering the technology needed to hit the continental United States with a long-range, nuclear-tipped missile, experts said Monday.

The North bragged earlier Monday in a report carried by state media that the test had been aimed at verifying its capability of carrying "a large-size heavy nuclear warhead." The launch of the new missile, referred to as the Hwasong-12, was overseen by North Korean leader Kim Jong Un, the state-run Korean Central News Agency said in a dispatch.

"The test-fire was conducted at the highest angle in consideration of the security of neighboring countries," the report said, adding that it had been "aimed at verifying the tactical and technological specifications of the newly-developed ballistic rocket capable of carrying a large-size heavy nuclear warhead."