North Korea, if left unchecked, is on an "inevitable" path to obtaining a nuclear-armed missile capable of striking the United States, Defense Intelligence Agency Director Lt. Gen. Vincent Stewart told a Senate hearing on Tuesday.

The remarks are the latest indication of mounting U.S. concern about Pyongyang's advancing missile and nuclear weapons programs, which the North says are needed for self-defense.

U.S. lawmakers pressed Stewart and Director of National Intelligence Dan Coats to estimate how far away North Korea was from obtaining an intercontinental ballistic missile(ICBM) that could reach the United States.