North Korea has missile systems with a range that puts the western coast of Alaska and some Pacific territories within reach. The underground test of a nuclear device in February escalated concerns about North Korea's ambitions, though it's not clear if it has the technology to arm a missile with a nuclear device.
A Defense Department report states that North Korea is trying to make advancements with its artillery and ballistic missile systems.
"These advances in ballistic missile delivery systems, coupled with developments in nuclear technology, are in line with North Korea's stated objectives to strike the U.S. homeland," the report said.
Researchers from Johns Hopkins University this week said North Korea could make gains in enriching nuclear material needed for a weapon, though there were underlying concerns about safety.
The Defense Department added that North Korea's weapons program isn't doing much to enhance its standing in the international arena.
"North Korea continues to fall behind the rising power of its regional neighbors, creating a widening military disparity and fueling its commitment to improving asymmetric and strategic deterrent capabilities as the primary guarantor of regime survival," the report said.