WASHINGTON (Sputnik) — The successful test comes "very close to crossing the threshold" of retaliatory action by the United States, Japan and [South] Korea, since the test demonstrated an accelerated pace of North Korean nuclear missile development," the letter noted.
"The Hwasong-12 significantly moves North Korea closer to having surprisingly demonstrated capability to strike the United States," the letter stated.
The letter also urged South Korea, Japan and the United States to increase the capacity of its ballistic missile defenses, including the deployment of additional missile defenses in the western-most US military base in Hawaii.
In addition, the letter recommended that the United States attempt to shoot down a future North Korean rocket.
North Korea claimed the missile was designed to carry a large-size nuclear warhead.
