North Korea fired a ballistic missile early Wednesday local time, according to South Korea's Joint Chiefs of Staff, CNN reported.
CNN confirmed the launch with the South Korean military leaders who said it was still flying.
"North Korea fired an unidentified ballistic missile early this morning from Pyongsong, South Pyongan, to the east direction. South Korea's Joint Chiefs of Staff is analyzing more details of the missile with the US side," said an official at South Korea's Joint Chiefs of Staff.
South Korea's Joint Chiefs of Staff said the South Korean military carried out a "precision missile strike drill" just minutes after North Korea's missile launch.
The precision missile strike matched the flight distance of the North Korean missile, and landed in waters off the east coast of South Korea.
The US military has also confirmed that there was a probable missile launch from North Korea.
"At approximately 1:30 p.m. Eastern Standard Time, we detected a probable missile launch from North Korea. We are in the process of assessing the situation and will provide additional details when available," said Pentagon spokesperson Col. Rob Manning.
White House press secretary Sarah Sanders said on Twitter that President Donald Trump "was briefed, while missile was still in the air, on the situation in North Korea."
Guam's Homeland Security/Office of Civil Defense posted on Facebook that they were notified that North Korea "conducted a ballistic missile launch" but there is no immediate threat to them or the Marianas.
US defense and intelligence officials had been growing increasingly puzzled as to why North Korean leader Kim Jong Un had not tested a ballistic missile since September.
Before Wednesday's test, North Korea had fired 22 missiles without active warheads during 15 tests since February. US officials say North Korea is continuing to develop its missiles, rocket fuel and engines, as well as targeting and guidance systems.
The US believes Pyongyang may be able to put a miniaturized warhead on a missile sometime in 2018 -- giving it the theoretical capability to launch a missile with a warhead atop that could attack the US.
North Korea has launched missiles at an unprecedented rate in 2017.
Pyongyang tested two missiles in July that demonstrated intercontinental range. It is currently testing a more advanced version of its existing ICBM, a US official told CNN earlier this month.