South Korea and the US confirm North Korea launched a single ballistic missile at a facility near Sinpo at 6:42 a.m. Korea time (5:42 p.m. ET).
"This is a blunt challenge to a series of Security Council resolutions. and an act to threaten the peace and safety of the global community as well as the Korean peninsula", South Korea's foreign ministry said in a statement.
Nuclear-armed North Korea on Wednesday fired a ballistic missile into the Sea of Japan, South Korea and the USA military said, days after Pyongyang warned of retaliation if the global community ramps up sanctions.
The latest launch came after President Donald Trump threatened the US was prepared to go it alone in bringing the North to heel if China did not step in, and ahead of a meeting with his Chinese counterpart Xi Jinping.
Some experts think North Korea has tried to make sure the two world leaders are aware Pyongyang has a bargaining chip in any forthcoming moves to clam down on its weapons programs.
North Korea has continued with military provocation this year.
U.S. Secretary of State Rex Tillerson acknowledged the launch in a brief statement but said the U.S. had spoken enough about North Korea and would not comment further.
Meanwhile, Secretary of State Rex Tillerson announced that the USA government will not release any more comment on North Korea's launch of another intermediate range ballistic missile.
Ralph Cossa, president of the Pacific Forum CSIS think-tank in Honolulu, said he was expecting North Korea would do something to coincide with the Trump-Xi summit, perhaps conduct a nuclear test.
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The North has fired missiles when South Korea hosted the 2010 Group of 20 summit and other events, and while top USA officials were traveling in the region.
Two weeks ago, the South Korean and United States militaries said they detected what they called a failed North Korean ballistic missile launch.
The command says it believes the missile was a KN-15 medium range ballistic missile.
This year, North Korea officials, including young leader Kim Jong Un, have repeatedly indicated an ICBM test, or something similar, could be coming, possibly as soon as April 15, the 105th birthday of North Korea's founding president and celebrated annually as "the Day of the Sun".
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Japan's Chief Cabinet Secretary Yoshihide Suga said the country lodged a strong protest over the launch. "And China will either decide to help us with North Korea, or they won't". Trump is likely to call on North Korea's main ally to exert more pressure on Pyongyang through measures including economic sanctions. The report was confirmed by South Korea's Office of the Joint Chiefs of Staff.
China maintains that the nuclear issue is one between North Korea and the United States, and China is doing its part by enforcing United Nations sanctions against Pyongyang and calling for dialogue to resume.
Last month, North Korea fired four ballistic missiles towards the Sea of Japan.