North Korea's attempt to launch an intermediate range ballistic missile off the country's east coast has failed, South Korea's Yonhap News Agency reported.
The failed launch follows North Korea's fourth nuclear test in January and a long-range rocket launch the next month, which led to fresh UN sanctions.
Yonhap said the failed launch appeared to be a Musudan missile with a range of more than 3000km.
The US military detected and tracked what it has assessed was the failed missile launch, a Defense Department spokesman said.
He said he had no details about the type of missile launched.
"We'll probably let North Korea characterise it themselves," he said.
The US State Department has seen the reports and is closely monitoring the situation on the Korean Peninsula, a department official said.
"We call again on North Korea to refrain from actions and rhetoric that further raise tensions in the region and focus instead on taking concrete steps toward fulfilling its international commitments and obligations," the official said.
Today is the anniversary of North Korean founding president Kim Il Sung's birthday, April 15, and is widely celebrated in the isolated country.
In 2012, the day was marked by a long range rocket launch attempt, which also failed.
On Thursday, North Korea deployed one or two Musudan ballistic missiles on its east coast in apparent preparation for the launch, South Korea's Yonhap News Agency reported, citing multiple South Korean government sources.