The U.S. military detected a failed North Korean missile launch attempt, with a missile exploding within seconds of its launch, a U.S. military spokesman said.

South Korea said the apparent North Korean test launch on Wednesday morning did not go off normally. But the U.S. military statement shed more light on the latest in a series of missile tests by the isolated, nuclear armed state that have raised alarm across the region.

"U.S. 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 U.S. Pacific Command, said in a statement, referring to an air field on North Korea's east coast.

"A missile appears to have exploded within seconds of launch," Benham said, adding that work was being carried out on a more detailed assessment.

The South Korean defence ministry said it was also conducting analysis for further details.

South Korea's Yonhap news agency said the missile may have exploded as it was launched, before reaching an altitude at which it could be detected by South Korean radar.

The launch comes as the U.S. envoy for North Korea nuclear programme, Joseph Yun, met his South Korean counterpart in Seoul to discuss a response to the North's weapons programmes.

North Korea has conducted two nuclear tests and a series of missile launches since the beginning of last year in defiance of U.N. resolutions. It is believed to be working to develop nuclear-tipped missiles that can reach the United States.

Earlier on Wednesday, Japan's Kyodo news agency reported North Korea may have launched several missiles from an area on its east coast, citing a Japanese government source.

The launch may have failed, Kyodo said, adding that the type of missile involved was not known.

Last year, North Korea launched several intermediate-range missiles from the same area but only one of the tests was successful.

Last week, U.S. Secretary of State Rex Tillerson visited Japan, South Korea and China and how to handle North Korea was a major issue in his talks.

Tillerson said all options, including a military one, were on the table if North Korea threatened South Korean or U.S. forces.

U.S. President Donald Trump on Sunday criticized North Korean leader Kim Jong Un, saying he was "acting very, very badly".

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.

A senior U.S. 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.

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.