North Korea may resume long-range ballistic missile tests over the next year, the U.S. Defense Intelligence Agency said in a report analyzing the country's military capabilities, warning that Pyongyang will continue to pose a "critical security challenge" for the United States and its allies.

The report, which was released Friday, is the latest warning about North Korea's efforts to beef up its military power despite not having tested intercontinental ballistic missiles or nuclear devices over the past several years.

Noting that North Korean leaders view nuclear arms as "critical to regime survival," the agency, which provides intelligence to the Defense Department, said, "Integrating a nuclear weapon with a ballistic missile and enabling that nuclear-armed missile to function reliably as a system is North Korea's ultimate operational goal."