North Korea fired an unidentified projectile into the sea off its east coast early Sunday local time, the South Korean military reported.
The missile flew about 310 miles. Military officials in South Korea are investigating what type of missile it was, the Korean Times reported.
The missile launch came as President Trump was hosting Japanese Prime Minister Shinzo Abe at his Mar-a-Lago estate in Florida. Trump and Abe made short statements about the launch in a joint appearance Saturday night.
"The United States of America stands behind Japan, it's great ally, 100%," Trump said.
Abe called the missile launch "absolutely intolerable."
"North Korea must fully comply with the relevant U.N. Security Council resolutions," Abe said through a translator.
In Washington, public affairs officers for the Defense Department and the State Department had no immediate comment on the report, according to The Associated Press.
The Korean peninsula has been tense since North Korean leader Kim Jong Un said in a New Year speech that the country was very close to testing an intercontinental ballistic missile capable of carrying nuclear weapons.
U.S. Defense Secretary James Mattis said last week when he visited South Korea that the United States would reply to any North Korean attempts to test nuclear weapons with an "effective and overwhelming" response.
Trump tweeted in January that though North Korea had said it was in the final stages of developing a nuclear weapon capable of reaching parts of the U.S., "It won't happen!"
North Korean has conducted more than 20 missile tests in 2016, despite UN sanctions for its actions.