North Korea poised to make unprecedented missile test

Pentagon officials are expecting North Korea to test fire an intermediate-range missile Friday morning, CBS News national security correspondent David Martin reports.

The missile in question is a Musadan, which is road mobile and has enough range to reach the Aleutians and Guam. It's never been tested before, so this is another step toward being able to threaten the United States with a nuclear weapon.

Friday, April 15 marks the birthday of Kim Il-sung, the "Great Leader" who rule North Korea from 1948 until his death in 1994.

On Saturday, North Korea said it had successfully tested a new intercontinental ballistic rocket engine that will give it the ability to stage nuclear strikes on the U.S.

The engine's ground test, if true, would be a big step forward for the North's nuclear weapons program, which saw its fourth atomic test earlier this year. But the North may still need a good deal of work before it can hit the U.S. mainland with nuclear missiles. South Korean officials say North Korea doesn't yet have a reliable intercontinental ballistic missile, let alone the ability to arm it with a nuclear warhead.

The test, announced by the North's official Korean Central News Agency, is only the latest in a string of what Washington and its allies consider North Korean provocations, including last month's launch of a medium-range ballistic missile that violated U.N. Security Council resolutions that prohibit any ballistic activities by North Korea. It was the North's first medium-range missile launch since early 2014.