Pence, who has called the North's failed missile test a day earlier "a provocation", said the USA and its allies will achieve its objectives through "peaceable means or ultimately by whatever means are necessary" to protect South Korea and stabilize the region.
South Korea's foreign ministry said that by conducting the latest test just a day after displaying a series of missiles, "North Korea has threatened the whole world".
The parade came amid growing global concern that North Korea could be preparing for a sixth nuclear test or a major missile launch, possibly its first flight test of an ICBM capable of reaching America.
Pence will be diving into a tense standoff along the Korean Peninsula with visits to South Korea and Japan beginning Sunday. The administration's immediate emphasis, the officials said, will be on increasing pressure on Pyongyang with the help of Beijing.
The latest launch came a day after the North held a defiant massive military parade in Pyongyang which showcased almost 60 missiles - including a suspected new intercontinental ballistic missile.
Analysts had expected North Korea to conduct a nuclear missile test around the time of his visit, possibly on Saturday as the nation celebrated the 105th birthday of its founder - Kim II Sung, the late grandfather of North Korea's current leader. He will aim to reassure allies in South Korea and Japan that the US will take appropriate steps to defend them against North Korean aggression.
US Vice President Mike Pence, who is in the area as part of previous scheduled trip, was briefed on the launch, administration officials said.
The UN Security Council has imposed six sets of sanctions against the North since its first nuclear test in 2006 - all of which have failed to halt its drive for what it insists are defensive weapons.
Sunday's launch was carried out around dawn from Sinpo, a site on North Korea's east coast where it has a shipyard.
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The White House believes that Sunday's test involved a medium-range ballistic missile that failed within 4-5 seconds after launch, and that it did not involve an intercontinental ballistic missile, the foreign policy adviser said.
Pence told reporters near the Demilitarized Zone separating North and South Korea that President Donald Trump is hopeful that China will use its "extraordinary levers" to pressure the North to abandon its weapons.
A North Korean missile exploded during launch on Sunday, U.S. and South Korean officials said. The good news is that after five seconds it fizzled out."Pence is in Seoul at the beginning of a 10-day trip to Asia in what his aides said was a sign of USA commitment to its ally in the face of rising tension".
Trump has repeatedly said he will prevent Pyongyang from its goal of developing a nuclear-tipped ballistic missile capable of reaching the mainland United States.
Pence, addressing an Easter service with American troops in South Korea, said the USA commitment to South Korea was unwavering.
China banned imports of North Korean coal on February 26, cutting off its most important export. North Korea regularly launches short-range missiles, but it is also developing mid-range and long-range missiles meant to target USA troops in Asia and, eventually, the US mainland.
"Why would I call China a currency manipulator when they are working with us on the North Korean problem?" Pence says, "North Korea would do well not to test his resolve".
Pyongyang has carried out five nuclear tests -- two of them a year ago -- and multiple missile launches, one of which saw three rockets come down in waters provocatively close to Japan last month.