The U.S. warned Sunday of unspecified action against North Korea if the regime of Kim Jong-un conducted another underground nuclear test following a failed missile launch.
"If it had been a nuclear test, then other actions would have been taken from the U.S.," said a White House foreign policy advisor traveling with Vice President Mike Pence in South Korea.
The advisor said that Kim "wants to do both, he wants to do a nuclear test and a missile launch. We've seen one. It doesn't prevent him from doing the other."
Separately, Army Lt. Gen. H.R. McMaster, the White House National Security Advisor, said President Donald Trump was exploring "a range of options" against North Korea but would prefer "to take action short of armed conflict, so we can avoid the worst."
McMaster said on ABC's "This Week" program that the U.S. was working with regional allies and China to "undertake all actions we can, short of a military option, to try to resolve this peacefully."
In a statement, Defense Secretary Jim Mattis said that Trump, who spent the weekend at his Mar-a-Lago estate in Florida, was in close touch with his military team on the crisis on the Korean peninsula.
"The President and his military team are aware of North Korea's most recent unsuccessful missile launch. The President has no further comment," Mattis said Saturday night, but Trump on Sunday put out tweets stressing U.S. resolve.
"Our military is building and is rapidly becoming stronger than ever before. Frankly, we have no choice," he said.
Trump said the U.S. was working with China "on the North Korea problem" and "we will see what happens."
Chinese State Councilor Yang Jiechi and Secretary of State Rex Tillerson "exchanged views on the situation on the Korean peninsula" in a phone conversation Sunday following North Korea's attempted missile launch, the state news agency Xinhua reported. Earlier, China had urged both the U.S. and North Korea to back away from war.
The foreign policy adviser accompanying Pence, speaking on background, said Trump was encouraged by his takeaway from meetings last week in Florida with Chinese President Xi Jinping.
The adviser said that China, North Korea's only ally, had stepped up economic pressure by turning back North Korean coal shipments. China could take other actions to rein in Kim but "I think it's a good first step," the adviser said.
U.S. Pacific Command said it detected a missile launch at about 6:20 a.m. Sunday Korean time from the area of Sinpo, a North Korean submarine base on the northeastern coast.
The missile "blew up almost instantly," Navy Cmdr. Dave Benham said in a statement. He said the command was analyzing what type of missile it may have been, and there was no immediate confirmation that it was one of the purported intercontinental ballistic missiles, or ICBMs, North Korea put on display at a huge military parade in Pyongyang Saturday.
"It looks like it was probably a medium-range ballistic missile," the White House foreign policy adviser said. "It failed after about 4.5 seconds. "It was not an ICBM."
South Korea's Foreign Ministry said in a statement that the Seoul government "strongly condemned" the launch and warned that Pyongyang would face "serious punitive measures" should it conduct a nuclear test or other provocations.
"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," the statement said.
The U.S. conducted its own show of force ahead of the attempted missile launch by canceling a port visit to Australia for the aircraft carrier Carl Vinson and its support ships, and instead sending the battle group to waters off Korea.
In Seoul Sunday, Vice President Pence, who was on a 10-day trip that will also take him to Japan, Indonesia and Australia, attended an Easter dinner for U.S. troops at the Yongsan military base.
He said of the failed missile launch, "This morning's provocation from the North is just the latest reminder of the risks each one of you face each and 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."
Pence spoke a day after North Korea rolled out what purported to be operational long-range missiles at a massive, goose-stepping parade to mark the 105th birthday of the Stalinist state's founder, Kim Il-Sung.
North Korean leader Kim Jong-un presided but remained silent at celebrations In Pyongyang of the 105th anniversary of the birthday of Kim Il-sung, his grandfather and first leader of the Democratic People's Republic of Korea (DPRK).
The North has traditionally used milestone events for demonstrations of military might. The next major anniversary will be April 25, marking the founding of North Korea's army, but analysts warned that a nuclear test, which would be North Korea's sixth, could come at any time.
Earlier this week, the authoritative 38 North website, run by the U.S.-Korea Institute at Johns Hopkins University's School of Advanced International Studies, said that satellite imagery showed that North Korea's Punggye-ri test site northeast of Pyongyang appeared "primed and ready" for a nuclear test.
The long lines of military hardware on display at the parade included what appeared to be three types of ICBM. One was the KN-08, believed to be the North's first attempt at developing an ICBM.
The second appeared to be a KN-14, a modified version of the KN-08. A third purported ICBM encased in a large tube may have been a new type of ICBM, according to South Korean analysts quoted by the New York Times.
In his ABC interview, McMaster spoke from Afghanistan, where he arrived Saturday to assess the request of Army Gen. John Nicholson, for thousands more U.S. troops to combat the Taliban and the ISIS offshoot called Islamic State-Khorasan Province.
On North Korea, McMaster said, "The President has made clear that he will not accept the United States and its allies and partners in the region being under threat from this hostile regime with nuclear weapons. And so we're working together with our allies and partners, and with the Chinese leadership, to develop a range of options."
-- Richard Sisk can be reached at Richard.Sisk@Military.com.