Pentagon to conduct first-ever ICBM intercept test

— -- The Pentagon's Missile Defense Agency will conduct its first-ever intercept test of an intercontinental ballistic missile (ICBM) next week, a nod to the growing threat from North Korea.

The test, scheduled for Tuesday, will involve launching an ICBM-class target from the Reagan Test Site on Kwajalein Atoll in the Republic of the Marshall Islands and a ground-based interceptor from Vandenberg Air Force Base in California.

If successful, the "kill vehicle" or intercept will collide with the ICBM test target mid-course over the Pacific Ocean. This is different than the Terminal High Altitude Area Defense (THAAD) system located in South Korea which would intercept the kill vehicle at a lower altitude in the missile's terminal stage.

This will be the 18th test of the ground-based interceptor. The last one, in June 2014, was the first success since 2008. The system is nine for 17 since 1999 with other types of target missiles. An ICBM target has never been tested before.

There are 32 ground-based interceptors at Fort Greely, Alaska and four at Vandenberg.

The Missile Defense Agency said in its FY2018 Budget Overview that it would deploy eight additional ground-based interceptors in Alaska by the end of 2017, for a total of 44 overall "to improve protection against North Korean and potential Iranian ICBM threats as they emerge."

The U.S. tests its ICBMs about twice every year. Earlier this month, Air Force Global Strike Command test launched an unarmed Minuteman III ICBM equipped with a single test reentry vehicle from Vandenberg. The reentry vehicle landed 4,200 miles away to the Kwajalein Atoll.

"These test launches verify the accuracy and reliability of the ICBM weapon system, providing valuable data to ensure a continued safe, secure and effective nuclear deterrent," the Air Force Global Strike Command said in a statement.

North Korea has spent the last decade working to develop an ICBM capable of reaching the continental United States. Though the country has conducted eight missiles tests thus far in 2017, none have proven to be an ICBM.

The last test North Korea conducted on May 21 was the successful launch of a KN-15 medium range ballistic missile that traveled just over 300 miles into the Sea of Japan.

But one week earlier, North Korea tested a KN-17 medium range ballistic missile, the first successful launch of its kind for the nation.

The Japanese Defense Minister Tomomi Inada told reporters that the missile reached an unprecedented altitude of 1,245 miles. Experts claim the missile would have flown a much greater distance if launched on a maximum trajectory, perhaps reaching military bases in Guam.

ABC News' Luis Martinez contributed to this report.