The Pentagon says its first-ever missile defense test involving an inter-continental ballistic missile was a success.

"The intercept of a complex threat-representative ICBM target is an incredible accomplishment," Vice Admiral Jim Syring of the Missile Defense Agency said.

Tuesday's test involved two separate missile launches. A simulated attack intercontinental ballistic missile was fired from a tiny island in the Pacific. A second missile was launched from Vandenberg Air Force Base in California.

WATCH: Pentagon conducts ICBM missile test

A simulated attack intercontinental ballistic missile was fired from a tiny island in the Pacific, while the second missile was launched from Vandenberg Air Force Base in California to intercept it.

The second missile successfully struck the first missile over the ocean, destroying it in mid-flight.

"From a diplomatic standpoint, it’s a tremendous message, and from a technical standpoint it shows that there are possibilities of actually mounting a type of defense that will knock at least some inter-continental ballistic missiles out of the sky before they reach their intended targets," former U.S. Air Force intelligence officer and current crisis management consultant Cedric Leighton told VOA.

Leighton said the system has had a problematic history and is about 50 to 55 percent effective.

"It is not something that is completely foolproof," he said.

The U.S. test followed North Korea's test of a short-range ballistic missile on Monday, which North Korea declared a success.

The missile landed in the Sea of Japan in what is known as Japan's exclusive economic zone, angering Tokyo.

The U.S. military deemed a test of the Ground-base The U.S. military deemed a test of the Ground-based Midcourse Defense System successful Tuesday. The U.S. military deemed a test of the Ground-based Midcourse Defense System successful Tuesday.

U.S. President Donald Trump said on Twitter that "North Korea has shown great disrespect for their neighbor, China, by shooting off yet another ballistic missile." But Trump gave China credit for "trying hard" to rein in North Korea's military ambitions.

China, North Korea's closest ally, has repeatedly said dialogue is the best way to make headway with dictator Kim Jong Un.

People watch as the Ground-based Midcourse Defense People watch as the Ground-based Midcourse Defense (GMD) element of the U.S. ballistic missile defense system launches during a flight test from Vandenberg Air Force Base, Calif., May 30, 2017. People watch as the Ground-based Midcourse Defense (GMD) element of the U.S. ballistic missile defense system launches during a flight test from Vandenberg Air Force Base, Calif., May 30, 2017.

At the United Nations Tuesday, U.S. Ambassador Nikki Haley said the Trump administration believes China is doing what she calls "backchannel networking" with North Korea on its nuclear program, and that the United States will keep up the pressure on China.

Haley also said the U.S. and China are working on the timing of when to come out with another resolution toughening sanctions on North Korea.