LOS ANGELES - US military officials said an interceptor missile launched Tuesday from a California military base shot down a simulated incoming warhead as part of a US defense system test.

The ground-based interceptor was launched from Vandenberg Air Force Base in Southern California, 250 km northwest to Los Angeles, at a mock-up of an intercontinental ballistic missile (ICBM) fired from the Reagan Test Site on Kwajalein Atoll in the Marshall Islands.

Officials said the interceptor missile travelled at 16,000 miles (27,040 km) per hour and hit its target over the Pacific Ocean.

The test came a day after the Democratic People's Republic of Korea (DPRK) tested its ninth ballistic missile this year that travelled 280 miles (473 km) before splashing down in the Sea of Japan.

Pentagon spokesman Navy Captain Jeff Davis said the test had been planned for some time and was not timed specifically as a response to the DPRK.

"In a broad sense, North Korea is one of reasons why we have this capability," Davis said.

"North Korea has expanded the size and the sophistication of its ballistic missile forces," he said in a statement.

The US interceptor has an uneven track record, having succeeded nine times out of 17 attempts against missiles in test since 1999, although the most recent test in June 2014 was a success.

"They continue to conduct test launches, as we saw this weekend, while also using dangerous rhetoric that suggests they would strike the United States homeland," Davis said.

The United States has 26 interceptors based at Fort Greely in Alaska and four at Vandenberg Air Force Base.

Last week, the Pentagon presented its 2018 budget to Congress, proposing spending 7.9 billion US dollars on missile defense, including 1.5 billion dollars for the ground-based mid-course defense program.