North Korea fired a missile across Japan's northern border.

It was North Korea's fifth provocative move in the past 10 days, and Japan advised residents of the northern islands to be vigilant following the missile launch.

Japan's assessment is that the missile landed in the Pacific Ocean. Japan has also suspended train services in the Hokkaido and Amari regions following the missile launch.

Earlier in 2017, North Korea fired a missile over Japanese airspace.

In the wake of North Korea's provocation, Japan has called an emergency meeting of the National Security Council.

South Korea said the missile travelled 4,000 km. South Korean President Yoon Suk Yool said that there will be a response to North Korea's move.

Flying a missile such a long distance allows North Korea's scientists to test missiles under more realistic conditions, said Ankit Panda of the U.S.-based Carnegie Endowment for International Peace.

"Compared to the usual highly lofted trajectory, this allows them to expose a long-range reentry vehicle to thermal loads and atmospheric reentry stresses that are more representative of the conditions they'd endure in real-world use," he said.

South Korean President Yoon Suk-yeol called the test "reckless" and said it would bring a decisive response from his country's military, its allies and the international community.

Speaking to reporters in Tokyo, Japanese Prime Minister Fumio Kishida called North Korea's actions "barbaric", and said the government would continue to gather and analyze information.

The launch over Japan was "not a productive path forward" but Washington remained open to talks, Daniel Kritenbrink, the top U.S. diplomat for East Asia, said during an online event hosted by the Institute for Korean-American Studies.