WASHINGTON, (Yonhap) -- North Korea will be a huge problem for the next U.S. president as it is perfecting capabilities to fly nuclear-armed missiles to the continental US, a former top intelligence official has warned.

Jami Miscik, a former deputy director for intelligence at CIA, made the remark in an interview with the Fortune magazine, noting that the US is not paying enough attention to the issue of North Korea, according to the report.

“The president-elect is going to face a problem with North Korea that none of his or her predecessors have faced. It is well on the way to becoming not just a nuclear power, but a power that is able to deliver a nuclear missile,” she was quoted as saying.

The remark is the latest in a series of warnings in the US of the seriousness of the North Korea problem in the wake of Pyongyang’s fifth nuclear test last month. That blast, together with ceaseless missile tests, sparked geunine fears that Pyongyang is making real progress in developing nuclear missiles.

Over the past week alone, the North twice tested its Musudan intermediate-range ballistic missile believed to be capable of reaching the US territory of Guam. Both tests failed as the missile exploded shortly after take-off.

“Musadan could probably hit Guam, but the next larger rocket would probably be able to hit the US,” Miscik was quoted as saying. “The fact these rocket launches are failing shouldn’t give anyone comfort, because they’re not failing for the same reason -- they fail and they fix that thing, and it might fail for another reason, but they’re advancing in terms of their capability.”

She said that the true threat to the US will come when North Korea figures out how to successfully launch a missile into space, re-enter the atmosphere, and hit its target, although noting this has yet to happen, according to the magazine.

A North Korea missile “could hit the continental United States at some point,” Miscik said.

She said the U.S. should work “very closely and privately with China” to rein in the North.

“I think the Chinese, Americans, South Korea, and Japan need to work together to figure out what to do about North Korea ... You want to shut down their ability to carry out their intentions,” she said, according to the magazine.