No planned response is expected from the Trump administration because the official, who spoke on condition of anonymity to discuss the administration's initial understanding of the launch, said there was no need for the U.S.to reinforce the failure.
The extended-range Scud missile in that earlier launch suffered an in-flight failure and fell into the sea off North Korea's east coast, according to USA imagery and assessments.
The North faced severe sanctions from the UN Security Council for a series of missile launches a year ago, in addition to two nuclear tests.
"The launch of the ballistic missile occurred near Sinpo", US Pacific Command spokesman CDR Dave Benham said.
Pence, speaking at Freedom House, a few metres from the military demarcation line that he described as a "frontier of freedom", said America's relationship with South Korea was "ironclad and immutable".
"This morning's provocation from the North is just the latest reminder of the risks each one of you face every day in the defense of the freedom of the people of South Korea and the defense of America in this part of the world", he told members of the USA military in South Korea. The administration's immediate emphasis, the officials said, will be on increasing pressure on Pyongyang with the help of Beijing.More news: Turkey arrests dozens in anti-referendum protests
North Korea might recognize that those actions would cross the red line and bring about a USA strike.
The US has sent a nuclear-powered aircraft carrier to the peninusla as North Korea today marks the 105th anninversary of the birth of its founder Kim Il Sung today.
The fact that any new ICBM would be in a canister is important because it means those missiles would likely be solid-fueled, analysts said. "Our military is building and is rapidly becoming stronger than ever before", he tweeted. "We will see what happens!"
Deputy national adviser K.T. McFarland briefed the president on the failed missile launch. Also, China should impose tight sanctions against North Korea for the sake of peace in Northeast Asia.
Into this tense environment, Pence made his first trip to the region since taking office in January.
He said: 'Our visit with the acting president [of South Korea], as we go into Seoul, the Vice President is going to reaffirm our commitment - ironclad US-ROK alliance.More news: US seeks Beijing's support for tougher sanctions against Kim
"The US is wrong because American politicians believe that China does not want to influence North Korea". He said the United States and President Donald Trump were making trouble in the region, citing Trump's tweets and the USA for moving an aircraft carrier into the region and for participating in its largest-ever joint military exercises with South Korea. He also said the situation on the Korean Peninsula was in a "vicious cycle" as tensions with the US and its allies deepen. In fact, the USA does not want dialogue with North Korea.
U.S. Vice President Mike Pence visits with troops at Camp Bonifas, just south of the DMZ.
North Korea's vice foreign minister says it will conduct its next nuclear test whenever its supreme headquarters sees fit.
The White House foreign policy adviser traveling with Pence told reporters that the type of missile that North Korea tried to fire on Sunday was medium-range, and that it exploded about 4 to 5 seconds after it was launched.
Outside experts say the North could conduct its sixth nuclear test at virtually anytime.More news: 'Blood, sweat and tears' not enough for beaten Barca
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