North Korea said on Saturday it would immediately suspend nuclear and missile tests, scrap its nuclear test site and instead pursue economic growth and peace, ahead of planned summits with South Korea and the United States.
Seoul officials see the talks as the starting point of President Moon Jae-in's initiative to denuclearize and build lasting peace on the peninsula, beginning with a freeze in the North's nuclear program and ending in its complete abolishment.
"I'm announcing today the United States of America will soon unveil the toughest and most aggressive round of economic sanctions on North Korea ever," Vice President Mike Pence said after meeting Japanese Prime Minister Shinzo Abe.
North Korea violated United Nations sanctions to earn nearly $200 million in 2017 from banned commodity exports, according to a confidential report by independent UN monitors, which also accused Pyongyang of supplying weapons to Syria and Myanmar.
South Korea on Tuesday offered talks with North Korea amid a standoff over its weapons programs, a day after North Korean leader Kim Jong Un said he was open to negotiations but that his country would push ahead with "mass producing" nuclear warheads.
Kim Jong-un on Monday warned the United States that he has a "nuclear button" on his desk ready for use if North Korea is threatened, but offered an olive branch to South Korea, saying he was "open to dialogue" with Seoul.