North Korea fired a ballistic missile on Monday, the South's military and Japan said, a move that ratcheted up tensions over the North's quest to develop weapons capable of hitting the United States.
The test is the latest launch by Pyongyang this year as the isolated regime steps up efforts to develop an intercontinental ballistic missile that can deliver a nuclear warhead to the continental United States.
The missile launches, and Pyongyang's threat to stage its sixth nuclear test, have prompted calls for tougher UN sanctions and a warning from US President Donald Trump that military intervention was an option under consideration.
South Korea's Joint Chiefs of Staff said in a statement that the "unidentified ballistic missile (speculated to be a Scud)" was fired from the North Korean coastal city of Wonsan at 5.09 am (2139 GMT) and travelled in an eastward direction.
"The flight range is about 450km (280 miles)," the statement said, adding that South Korean and US experts were analysing the event for further detail.
Japan's chief cabinet secretary, Yoshihide Suga, told reporters the missile appeared to have fallen into the country's Exclusive Economic Zone (EEZ) - waters extending 200 nautical miles from its coast.
"Our country can never tolerate repeated provocative actions by North Korea," he said, condemning the launch.
The regime has carried out two atomic tests and dozens of missile launches since the beginning of last year, with multiple sets of UN sanctions failing to halt its weapons push.
US authorities tracked the six-minute flight until it crashed into the Sea of Japan, the US Pacific Command said.
"We continue to monitor North Korea's actions closely," the Pacific Command said in a statement, adding that it was working on a more detailed assessment of the launch from near the country's Wonsan Airfield.
"US Pacific Command stands behind our ironclad commitment to the security of our allies in the Republic of Korea and Japan.
"The North American Aerospace Defense Command (NORAD) assessed that the missile launch from North Korea did not pose a threat to North America."
In Washington, a National Security Council spokesman said President Trump had been briefed on the launch.
