The Pentagon scored an important success Tuesday in a test of its oft-criticized missile defense program, destroying a mock warhead over the Pacific with an interceptor that is key to protecting U.S. territory — including Hawaii — from a North Korean attack.

It was the first live-fire test against an intercontinental ballistic missile target for in-ground interceptors in Alaska and California.

Vice Adm. Jim Syring, director of the U.S. Missile Defense Agency, called the test result “an incredible accomplishment.”

“This system is vitally important to the defense of our homeland, and this test demonstrates that we have a capable, credible deterrent against a very real threat,” Syring said in a written statement.

Despite the success, the $244 million test didn’t confirm that under wartime conditions the U.S. could intercept an ICBM fired by North Korea.

U.S. Rep. Tulsi Gabbard, D-Hawaii, also noted it was a positive step, but said more needs to be done to protect the state.

“North Korea’s continued aggression and increasing capabilities, including another ballistic missile launch (Monday), underscore the importance of making sure our missile defense system is able to effectively protect Hawaii and our country,” Gabbard said in an email. “(Tuesday’s) successful test of our missile defense capabilities, specifically against an (ICBM) threat, is a positive development which further reinforces the need for more tests and development of our ballistic missile defense systems.”

Adm. Harry Harris, head of U.S. Pacific Command, recently spoke about the threat posed to Hawaii, and the “need to ensure our missile defense infrastructure includes layers of protection for Hawaii,” Gabbard said.

Harris told Congress in April that North Korean leader Kim Jong Un “is clearly in a position to threaten Hawaii today,” and said a defensive radar for the islands is planned and that installing ICBM interceptors in the islands is being discussed.

“I’m continuing to look at all options available to us and pursuing those which will ensure Hawaii is defended from simple and complex attacks now, and into the future,” Gabbard said.

Among the options for Hawaii, which is far from interceptor missiles in Alaska that theoretically provide protection, is activating the Aegis Ashore missile defense facility on Kauai — used only for testing now — in times of emergency, officials have said.

“Initial indications are that the test met its primary objective, but program officials will continue to evaluate system performance based upon telemetry and other data obtained during the test,” Syring said.

The most recent intercept test, in June 2014, was successful, but the longer track record is spotty. Since the system was declared ready for potential combat use in 2004, only four of nine intercept attempts have been successful.

“This is part of a continuous learning curve,” said Navy Capt. Jeff Davis, a Pentagon spokesman, ahead of Tuesday’s test. The Pentagon is still incorporating engineering upgrades to its missile interceptor, which has yet to be fully tested in realistic conditions.

North Korea on Monday fired a short-range test ballistic missile that landed in Japan’s maritime economic zone.

In Tuesday’s U.S. test the Missile Defense Agency launched an interceptor rocket from an underground silo at Vandenberg Air Force Base in California. The target was an intercontinental-range missile fired from a test range on Kwajalein Atoll.

Hawaii’s Sea-Based X-Band Radar, positioned far off the isles, acquired and tracked the target as part of what’s formally known as the Ground-based Midcourse Defense system.

A 5-foot-long “kill vehicle” released from the interceptor zeroed in on the ICBM-like target’s mock warhead outside Earth’s atmosphere and obliterated it by sheer force of impact, the Pentagon said.

The target simulated an ICBM, meaning it flew faster than missiles used in previous intercept tests, according to Chris Johnson, a Missile Defense Agency spokesman.

The Pentagon likens the defensive tactic to hitting a bullet with a bullet. With congressional support the Pentagon is increasing by the end of this year the number of deployed interceptors, based in California and Alaska, to 44 from the current total of 36.