The launch attempt was made from near the city of Wonsan, on North Korea's east coast, the same place from where it launched several intermediate-range missiles last year, all but one of which failed.
"US Pacific Command detected what we assess was a failed North Korean missile launch attempt ... in the vicinity of Kalma," Commander Dave Benham, a spokesman for US Pacific Command, said in a statement, referring to an air field in Wonsan.
"A missile appears to have exploded within seconds of launch," Benham said, adding that work was being carried out on a more detailed assessment.
A South Korean military official told Reuters the missile appeared to have exploded just after it was launched.
"It may have exploded right after it took off from a launch pad," said military official, who declined to be identified.
It was not clear what type of missile it was. The South Korean defence ministry said it was conducting analysis to determine further details.
The increasing frequency of the missile tests has fuelled a growing sense of urgency over how to respond to the isolated, unpredictable state.
North Korea launched four ballistic missiles from near its west coast on March 6 and this week conducted a rocket engine test that its leader, Kim Jong Un, said opened "a new birth" of its rocket industry.
The latest launch came as the US envoy for North Korea policy, Joseph Yun, met his South Korean counterpart in Seoul to discuss a response to the North's weapons programmes.
Just last week US Secretary of State Rex Tillerson visited Japan, South Korea and China and how to handle North Korea was a major issue in his talks.
Speaking in Seoul on Friday, Tillerson said a policy of strategic patience with North Korea had ended and all options, including a military one, were on the table if North Korea threatened South Korean or US forces.
North Korea has conducted two nuclear tests and a series of missile launches since the beginning of last year in defiance of UN resolutions. It is believed to be working to develop nuclear-tipped missiles that can reach the United States.
US President Donald Trump rebuked Kim on Sunday, saying the North Korean leader was "acting very, very badly."
A senior US official in Washington told Reuters on Monday that the Trump administration was considering sweeping sanctions as part of a broad review of measures to counter North Korea's nuclear and missile threat.
The United States is also deploying an advanced missile-defence system in South Korea. But China objects to the Terminal High Altitude Area Defense system, saying its powerful radar can penetrate deep into its territory, undermining its security.
Undaunted by the possibility of even tougher sanctions aimed at cutting North Korea off from the global financial system, a North Korean diplomat said his government would pursue an "acceleration" of its nuclear and missile programmes.
This includes developing a "pre-emptive first strike capability" and an inter-continental ballistic missile, said Choe Myong Nam, deputy ambassador at the DPRK (North Korean) mission to the United Nations in Geneva.