Speaking on his way home from the Winter Olympics in South Korea, Mr Pence said there was “no daylight” between the two allies on the issue.
The Games has seen better ties between the two Koreas despite tensions over the North’s nuclear programme.
But US has distanced itself from the North Korean overtures.
On Saturday North Korean leader Kim Jong-un invited the South’s President, Moon Jae-in, to Pyongyang for talks.
It would be the first summit in more than a decade between Korean leaders. Mr Moon said the Koreas should “make it happen” and encouraged the North to return to negotiations with the US.
But Pyongyang’s nuclear programme will hang over any attempts to bring the countries closer together.
The US administration has sought to maintain pressure on North Korea through sanctions and tough rhetoric from President Donald Trump.
Speaking to reporters during a flight on Saturday, Mr Pence said: “There is no daylight between the United States, the Republic of Korea and Japan on the need to continue to isolate North Korea economically and diplomatically until they abandon their nuclear and ballistic missile programme.”
The handwritten invitation to President Moon was delivered by Mr Kim’s influential sister, Kim Yo-jong, at a landmark meeting in the presidential palace in Seoul, as the Games opened on Saturday.
Ms Kim and the North’s ceremonial head of state Kim Yong-nam made up the most senior delegation from the North to visit the South since the Korean War in the 1950s.
The invitation puts Mr Moon in a difficult position as he had promised to engage with the North, but his US ally is cautious of Seoul falling for North Korea’s charm offensive.
Despite the public shows of friendliness, experts have warned the underlying tensions have not gone away.
At the opening ceremony for the Games, Mr Pence, Kim Yo-jong and Kim Yong-nam were seated in close proximity to each other.
Mr Pence stayed seated when South and North Korean athletes marched together under a unified flag, and also skipped a dinner with the North Korean delegation. (Courtesy BBC)