A North Korean missile appeared to have exploded on Wednesday just after it was launched, the U.S. and South Korean militaries said after detecting the latest in a series of weapons tests by the nuclear-armed state that have alarmed the region.

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.

"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 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 defense ministry said it was conducting analysis to determine further details.

The increasing frequency of the missile tests has fueled 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 U.S. envoy for North Korea policy, Joseph Yun, met his South Korean counterpart in Seoul to discuss a response to the North's weapons programs.

Just 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.

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 U.S. forces.

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.