A North Korean missile "blew up almost immediately" on its test launch on Sunday, the U.S. Pacific Command said, hours before U.S. Vice President Mike Pence was due in South Korea for talks on the North's increasingly defiant arms program.
The failed launch from North Korea's east coast, ignoring admonitions from major ally China, came a day after North Korea held a military parade in its capital, marking the birth anniversary of the state founder, in which what appeared to be new long-range ballistic missiles were on display.
South Korea said the combined show of force "threatened the whole world".
Pence is due in Seoul at the start of a 10-day trip to Asia in what his aides said was a sign of the U.S. commitment to its ally in the face of the rising tension.
The U.S. nuclear-powered USS Carl Vinson aircraft carrier strike group is also heading to the region
A U.S. Navy attack on a Syrian airfield this month with Tomahawk missiles raised questions about U.S. President Donald Trump's plans for reclusive North Korea, which has conducted several missile and nuclear tests in defiance of U.N. sanctions, regularly threatening to destroy the South and the United States.
South Korea, which hosts 28,500 U.S. troops to help counter the threats, warned of punitive action if the launch led to further provocations such as a nuclear test or a long-range missile launch.
"North Korea showing a variety of offensive missiles at yesterday's military parade and daring to fire a ballistic missile today is a show of force that threatens the whole world," South Korea's Foreign Ministry said in a statement.
The South's National Security Council said it would respond strongly to any further provocation.
The North has warned of a nuclear strike against the United States if provoked. It has said it has developed and would launch a missile that can strike the mainland United States but officials and experts believe it is some time away from mastering the necessary technology.
"The North attempted to launch an unidentified missile from near the Sinpo region this morning but it is suspected to have failed," South Korea's Office of the Joint Chiefs of Staff said in a statement.
The U.S. Pacific Command said the missile "blew up almost immediately", adding the type of missile was being analyzed.
China has spoken out against North Korea's missile and nuclear tests and has supported U.N. sanctions. China on Friday again called for talks to defuse the crisis.
Sinpo, where the Sunday launch took place, is the site of a North Korean submarine base and where the North has tested the submarine-launched ballistic missile it is developing.
“It appears today’s launch was already scheduled for re-launching after the earlier test-firing,” said Kim Dong-yub, a military expert at Kyungnam University's Institute of Far Eastern Studies in Seoul.
“This launch can possibly be a test for a new type of missile or an upgrade,” Kim said.
Tension had escalated sharply in the region amid concerns that the North may conduct a sixth nuclear test or a ballistic missile test launch around the April 15 birth anniversary of founding father Kim Il Sung it calls the "Day of the Sun".
The White House has said Trump has put the North "on notice".