China is North Korea's closest ally, and Trump has expressed irritation that the North's primary trading partner has failed to curb Kim's development of nuclear weapons and missile technology.
Pence sought to explain the policy in meetings with South Korea Acting President Hwang Kyo-ahn and other top officials in Seoul at the start of the trip, which will also include stops in Japan, Indonesia and Australia.
Despite the dangers of crossing the landmine and barbed-wire strewn DMZ, several North Korean soldiers have defected in this way.
The United States, its allies and China are working together on a range of responses to North Korea's latest failed ballistic missile test, Trump's national security adviser said on Sunday, citing what he called an global consensus to act.
He said: "It is clear to everybody that the USA is hellbent on unsafe sabre rattling in North Korea".
The era of strategic patience is over. He went on to say, "As the President has made very clear, either China will deal with this problem or the United States and our allies will".
Kim said the DPRK's policy is shaped by the Trump administration's push for "high intensity sanctions" against the country, deploying tactical nuclear weapons in South Korea and launching military action aimed at "beheading" the North's leadership headed by Kim Jong Un. Though Russia critics welcomed Trump's newly hardened tone, there's less enthusiasm from America's allies in Asia, who fear the US could overlook China's more aggressive posture toward its neighbors. Under rainfall, Pence later stood a few meters from the military demarcation line outside Freedom House, gazing at the North Korean soldiers across the border.
Before adding that his country "is ready to react to any mode of war desired by the USA". A US armada, including an aircraft carrier and multiple warships, has been deployed to the Korean Peninsula.
Kim Song Gyong, director general of the European Department of the Foreign Ministry in Pyongyang, told Reuters that if Washington made "the slightest movement" to make a nuclear strike on North Korea, Pyongyang would strike first and "destroy the aggressors without any mercy".
China has put forward a "dual-track approach" and a "suspension for suspension" proposal to ease tensions on the peninsula and create conditions for peace talks, he said.
"We've seen China begin to take some actions to bring pressure on North Korea but there needs to be more", Pence said. But critics say sending military aircraft and vessels is a sensitive issue for South Korea because of its bitter memories from the Japanese military aggression and colonization in the first half of 1900s.
The US Vice-President will leave for Japan on Tuesday.
Pence visited a military base near the DMZ, Camp Bonifas, for a briefing with military leaders and to meet with American troops stationed there.
Secondly, North Korea is actively working on multiple launches. "But dialogue for the sake of having dialogue is meaningless".
"Last decade, when China's financial institutions were named as potential money laundering concerns by the U.S. Treasury, China halted fuel shipments to [North Korea] in order to get them to return to multilateral talks", Stephen Yates, former deputy assistant to the Vice President for National Security Affairs and D.C. Intel Advisory CEO, told FOX Business.
But at every step of the way, North Korea answered our overtures with willful deception, broken promises and nuclear and missile tests.
Pence will meet with Japan's Deputy Prime Minister Taro Aso on Tuesday, kicking off talks in Tokyo that the White House hopes will open doors in Japan for US -made products and attract Japanese investment for infrastructure projects in the United States.
Trump has stated that he wants to see China take a larger role in pressuring the North Korean regime.