"The plans are ongoing. We believe that the summit will likely occur after the first of the year but the when and the where of that is still being worked out," Pence told reporters after his meeting with South Korean President Moon Jae-in on Thursday in Singapore.
Pence and Moon held a meeting on the sideline of a Southeast Asian Nations (ASEAN) Summit in Singapore.
"We don't want to repeat the mistakes that prior administrations, frankly in both political parties, have made over the last several decades where promises are made, sanctions are lifted, economic support comes and then promises are broken," he said.
Denuclearization talks between the U.S. and North Korea have been slow to make a significant progress. A meeting that was scheduled for last week in New York between U.S. Secretary of State Mike Pompeo and his North Korean counterpart was postponed without an immediate plan to resume.
Moon said in a speech to leaders of Asia and Pacific countries that the second summit between Trump and Kim will take place "soon."
"The reciprocal visit by Chairman Kim to Seoul and the second summit between the U.S. and North Korea will happen soon," he said.
"North Korea continues to take steps to achieve denuclearization. It dismantled a nuclear test site and promised to destroy a missile test facility and stand. Although it made a condition for a corresponding measure from the U.S., it's a big step they mentioned the possibility of permanently closing its Yongbyon nuclear facility," he said.
South Korea's presidential office said Moon and Pence talked about practicalities related to the second summit between Trump and Kim.
"Moon and Pence discussed situations on the Korean Peninsula and preparations for the second U.S.-North Korea summit," Kim Eui-kyeom, South Korea's presidential spokesman said in a briefing on Thursday in Singapore.
Kim said to reporters that Moon and Pence didn't talk about lifting sanctions on North Korea and Pence asked Moon to communicate with the North more closely.
Pence has reiterated the need to maintain sanctions on North Korea until it reaches a complete denuclearization, in a meeting with Japanese Prime Minister Shinzo Abe in Tokyo on Tuesday.