The North conducted two nuclear tests and 24 ballistic missile tests last year, defying six UN Security Council sanctions resolutions banning any testing, and it has launched more missiles this year including a failed attempt at the weekend.
North Korea is preparing for "any mode of war" triggered by USA military action, Pyongyang's envoy to the United Nations warned Monday, saying his country would respond to a missile or nuclear strike "in kind".
During a visit to the Demilitarized Zone between North and South Korea yesterday, Pence pointed to the new president's recent strikes on a Syrian airbase and an Islamic State complex in Afghanistan as a warning to Pyongyang not to underestimate the administration's resolve.
Pence said he had spoken with US President Donald Trump and by 2020 some 60 percent of the US naval fleet would be in the region and Japan's role will grow.
The vice president reassured South Korea that the United States has its back in the face of mounting threats from North Korean dictator Kim Jong-Un.
Late on Monday, Pence reiterated in a joint statement alongside South Korea's acting president, Hwang Kyo-ahn, that "all options are on the table" and said any use of nuclear weapons by Pyongyang would be met with "an overwhelming and effective response".
"We should stay on our toes to protect our territory and people's lives", Hwang said.
North Korea used Chinese-made trucks to display missiles at a massive military parade last week, according to photographs released by state media, underlining the difficulty in enforcing United Nations sanctions against the isolated state. It has said it has developed a missile that can strike the mainland United States, but officials and experts believe it is some time away from mastering the necessary technology, including miniaturising a nuclear warhead.
"It is our belief by bringing together the family of nations with diplomatic and economic pressure we have a chance of achieving a freeze on the Korean Peninsula", Mr Pence said.
He has sent a navy strike group towards the Korean Peninsula, and the US and South Korea are moving ahead with the early deployment of a controversial missile defence system.
Ahead of the "Day of the Sun" on April 15, one of the biggest celebrations in the North Korean calendar, North Korea analysts said satellite images showed Pyongyang was "primed and ready" for a sixth nuclear test.
In early March, the North simultaneously fired four ballistic missiles off its east coast, three of which fell provocatively close to Japan, in what it said was a drill for an attack on US bases in the country.
When asked about military intervention in North Korea, Mr Trump said: "I don't want to telegraph what I'm doing or what I'm thinking".
U.S. 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. They also say greater Chinese cooperation is vital.
The press secretary said it was too early to say the extent of the action China was taking.
For weeks Washington has pushed the view that Beijing is the key to solving the North Korean nuclear problem.
Chinese Foreign Minister Wang Yi repeated China's line that the crisis could only be resolved by diplomacy. The administration first began negotiations with his grandfather, Kim Il-Sung in 1993, before completing them with his father, Kim Jong-Il in 1994.
Chief Cabinet Secretary Yoshihide Suga told reporters over the weekend that Japan might push ahead with a revised, 11-nation version of the TPP despite the USA rejection of the trade accord.
"China continues to have both economic and political influence over North Korea". Since the North Korean ships were turned away, analysts have noted China is not using almost as much coal as it did for a few years.
For his part, Abe called for a peaceful solution to the crisis with North Korea, as reported by AFP.