North Korea has test-fired a medium-range ballistic missile from its eastern port of Sinpo into the Sea of Japan.
South Korea's defence ministry said the missile flew about 60km (40 miles).
It is the latest in a series of tests which the North has been conducting in pursuit of its goal of developing a nuclear missile.
The launch comes on the eve of a visit by China's President Xi Jinping to the US to meet President Donald Trump.
The two will discuss how to rein in North Korea's nuclear and missile programmes as the US steps up the pressure on China, a historic ally of Pyongyang, to help more on the issue.
Mr Trump said in a recent interview that Washington was ready to act without Beijing's co-operation: "If China is not going to solve North Korea, we will."
The North is banned from any missile or nuclear tests by the UN, though it has repeatedly broken those sanctions.
The US military's Pacific Command said it appeared to have been a KN-15 medium-range ballistic missile.
"The North American Aerospace Defense Command (Norad) determined the missile launch from North Korea did not pose a threat to North America," it said.
US Secretary of State Rex Tillerson described the launch as "yet another" intermediate range ballistic missile, adding: "The United States has spoken enough about North Korea. We have no further comment."
Japan called the launch "provocative", while South Korea condemned it as "a blunt challenge" to the UN and "a threat to the peace and safety of the international community as well as the Korean peninsula".
Last month, North Korea fired four ballistic missiles towards the Sea of Japan from the Tongchang-ri region, near the border with China.
Japanese PM Shinzo Abe called it a "new stage of threat".
Last week, the US Treasury slapped sanctions on 11 North Korean business representatives and one company.
On Tuesday US politicians overwhelmingly backed a bill relisting the North as a state sponsor of terror.
North Korea responded by warning that it will retaliate if the international community steps up sanctions, saying the US was forcing the situation "to the brink of war".
China has long been North Korea's closest diplomatic ally and trading partner, but the relationship has become increasingly strained over Pyongyang's refusal to halt nuclear and missile testing.
There are fears that Pyongyang could eventually develop the ability to launch long-range nuclear missiles capable of striking the mainland US.
In the interview to the FT, Mr Trump added: "China has great influence over North Korea. And China will either decide to help us with North Korea, or they won't. And if they do that will be very good for China, and if they don't it won't be good for anyone."