North Korea’s latest ballistic missile test that flew over Japan on Tuesday is “another provocation” and a big concern, the U.S. disarmament ambassador said.

U.S. envoy Robert Wood told reporters in Geneva that Washington still needs to do “further analysis” of the missile that flew over Japan’s northern Hokkaido island into the sea.

“It’s another provocation by North Korea, they just seem to continue to happen.

This is a big concern of course to my government and to a number of other governments,” Wood said before a session of the UN-sponsored Conference on Disarmament where North Korean Ambassador Han Tae Song was to speak.

The test, one of the most provocative ever from the reclusive state, came as U.S. and South Korean forces conduct annual military exercises on the peninsula, to which North Korea strenuously objects.

North Korea has conducted dozens of ballistic missile tests under young leader Kim Jong Un, the most recent on Saturday, but firing projectiles over mainland Japan is rare.

“North Korea’s reckless action is an unprecedented, serious and a grave threat to our nation,” Japanese Prime Minister Shinzo Abe told reporters.

Abe said he spoke to U.S. President Donald Trump on Tuesday and they agreed to increase pressure on North Korea.

Trump also said the United States was “100 per cent with Japan”, Abe told reporters.

South Korea’s military said the missile was launched from near the North Korean capital, Pyongyang, just before 6 a.m. (2100 GMT Monday) and flew 2,700 km, reaching an altitude of about 550 km.

Four South Korean fighter jets bombed a military firing range on Tuesday after President Moon Jae-in asked the military to demonstrate capabilities to counter North Korea.

South Korea and the United States had discussed deploying additional “strategic assets” on the Korean peninsula, the presidential Blue House said in a statement, without giving more details.

North Korea remained defiant.