Previously, the North Korean military threatened to unleash a "merciless" response against American targets, including the naval task force the USA recently deployed.
Tension had escalated sharply amid concern the North may conduct a sixth nuclear test or a ballistic missile test around Saturday's 105th birth anniversary of founding father Kim Il Sung, what it calls the "Day of the Sun".
North Korea displayed what appeared to be new long-range and submarine-based missiles on the 105th birth anniversary of its founding father, Kim Il Sung, on Saturday, as a nuclear-powered US aircraft carrier group steamed towards the region.
South Korea said the combined show of force "threatened the whole world".
Pence, addressing an Easter service with American troops in South Korea, said the USA commitment to South Korea was unwavering.
Washington has sent a nuclear-powered aircraft carrier group towards the region.
North Korea warned the United States to end its "military hysteria" earlier on Saturday or face retaliation as a USA aircraft carrier group steamed towards the region.
"Though analysts questioned what was inside the missile shells, they said the appearance of a submarine-launched ballistic missile shows North Korea is progressing with its plan to launch missiles from anywhere in the sea".
North Korea did not go through with a possible nuclear test Saturday, after the United States demonstrated a credible threat of military force in the region and China increased economic restrictions against its economically dependent ally.
"Whatever comes from the U.S. politicians, if their words are created to overthrow the DPRK system and government, we will categorically reject them", he said.
In another report by CNN, North Korea's new missiles and submarines were detailed despite China's disapproval.
The administration's immediate emphasis, the officials said, will be on increasing pressure on Pyongyang with the help of Beijing.
During a fellowship meal after the services, he said the tensions on the Korean peninsula had put into sharp focus the importance of the joint U.S. Pence likely wouldn't make the trip if any belligerent actions were pending.
Pence had been briefed on the failed launch en route to Seoul and had been in touch with Trump, White House aides said.
The North launched a ballistic missile from the same region this month, ahead of a summit between the United States and China in Florida to discuss the North's arms programme.
"If they are unable to do so, the USA, with its allies, will! China is willing to give support to all of them", he said.
Its national airline, Air China, has cancelled some flights to the North Korean capital, Pyongyang, due to poor demand but it has not suspended all flights there, it said on Friday.
While China opposes the North's nuclear program it is reluctant to take harsh measures that would cause instability at its border and that would increase US power in the region.
It has carried out five nuclear tests - two of them past year - and multiple missile launches, one of which saw several rockets come down in waters provocatively close to Japan last month.