"We are with you 100 per cent", he said.
North Korean state media last week warned of a nuclear attack on the United States at any sign of American aggression, but the White House said there was no evidence it possessed that capability.
"I issue a clear warning to the Kim Jong-un regime of North Korea", Ahn said.
Since entering office, President Donald Trump, like his predecessor, Barack Obama, has pressed China to use its political and economic leverage over North Korea, its once-close ally.
China has recently shown "tangible indications" that it is cooperating with the U.S.to turn up the pressure on Pyongyang, a senior State Department official said Monday.
Mr Pence and Mr Abe agreed they needed to persuade China to play a larger role in dealing with North Korea, a Japanese government spokesman said. Developing a hydrogen bomb is also a declared priority of North Korea, officially the Democratic People's Republic of Korea or DPRK.
North Korea has a long history of portraying the mock violent demise of the United States in animated videos, usually released to mark national holidays.
USA officials say tougher sanctions could include an oil embargo, a global ban on North Korea's airline, intercepting cargo ships and punishing Chinese banks doing business with Pyongyang.
North Korea has repeatedly ignored China's calls for denuclearization and other steps to calm tensions on the peninsula, and relations between the two are believed to have sunk to their lowest level in years.
North Korea's isolated totalitarian regime marked the birthday of founder Kim Il Song over the weekend with a massive military parade and an attempted missile launch, but the spectacle wouldn't have been complete without a new animated video portraying a fiery end to the United States.
The Trump administration has said military action remains an option for dealing with North Korea.
In Beijing, Chinese Foreign Minister Wang Yi made a fresh appeal for calm.
Meanwhile, China's once-thriving relationship with South Korea has hit the rocks over Beijing's strenuous objections to Seoul's deploying of an advanced US anti-missile system.
China defended its trade practices on Tuesday after Chinese-made vehicles were seen towing ballistic missiles during a North Korea military parade despite global sanctions against selling military hardware to Pyongyang.
"This exercise will rigorously test our aerial combat capability and highlights the ironclad commitment between the USA and (South Korea), and the multifaceted capabilities we possess in this theater", Lt. Gen. Thomas W. Bergeson, 7th Air Force commander, told Yonhap News.