"The US still has an important leverage like economic sanctions. Thus the country won't lose much even if it takes trust-building measures," said Yoon, who served as South Korea's top diplomat during the presidency of Roh Moo-hyun.

In particular, he stressed that the invitation of a North Korean economic mission to the US would be an important gesture to promote political reconciliation.

He also suggested that the US and North Korea set up liaison offices in Pyongyang and Washington, saying, "If the North accepts American inspectors to its Yongbyon nuclear complex, the US would establish a base camp for at least 100 Americans (in the North)."

Yoon largely echoed the opinions of South Korean President Moon Jae-in, who told Fox News in New York last week that exchanges of liaison offices and economic missions between the US and North Korea would speed up the latter's denuclearization.

Prof. Kim Byung-yeon of Seoul National University said at the same forum that the US should put forth more concrete economic support measures for North Korea to implement its denuclearization.

"North Korea has already entered a phase of an open economy, and Chairman Kim Jong-un of the State Affairs Commission should adjust his policies to the trend," the professor said. (Yonhap)