North Korea launched an unidentified ballistic missile Tuesday.
South Korean Military officials are quoted as saying the missile flew on an eastward trajectory and that authorities are analyzing the launch in cooperation with the U.S. military.
"We detected a probable missile launch from North Korea. We will provide additional information as available," Pentagon spokesman Army Col. Robert Manning said.
The United States is "not surprised" by the development, a U.S. intelligence official told VOA.
White House Press Secretary tweeted President Donald Trump "was briefed, while missile was still in the air, on the situation in North Korea."
The last ballistic missile launch by North Korea was in September. It is still unclear what type of missile was launched Tuesday.
In Japan, the Cabinet crisis team has been summoned for an emergency meeting. Japan's chief Cabinet secretary said Tokyo "strongly protests" the launch.
The latest North Korean launch comes as the U.S. and South Korea are preparing a five-day joint exercise called “Vigilant Ace” from December 4-8 with thousands of military personnel and more than 230 aircraft, including six F-22 Raptor fighter jets deployed to South Korea for the first time.
Pyongyang routinely condemns such military drills using belligerent language and military threats.
Pentagon correspondent Carla Babb, National Security correspondent Jeff Seldin, White House correspondent Steve Herman and Seoul correspondent Daniel Schearf contributed to this report