The prospect of holding "exploratory" nuclear talks with North Korea depends on how much the United States lowers its bar for resuming formal denuclearization negotiations, a U.S. expert said Wednesday.

The possibility of "exploratory talks" with Pyongyang resurfaced this week as South Korea's chief nuclear envoy, Hwang Joon-kook, said after a meeting with his U.S. counterpart, Amb. Sung Kim, that the five parties in the six-party nuclear talks would seek such talks without preconditions.

The term "exploratory talks" refers to a compromise form of negotiations aimed at meeting both Pyongyang's demand for an unconditional resumption of talks and the U.S. insistence that any formal negotiations should begin only after Pyongyang takes concrete steps toward denuclearization.

Such talks, if realized, would mark the first denuclearization talks with North in more than six years.

Senior officials have also said that the five countries, especially the U.S. and China, have narrowed their differences on the preconditions for resuming the six-party talks and they want to present the preconditions in exploratory talks with the North and see how Pyongyang reacts.

"It really depends on what's going on with the preconditions.

The chances of the North Korean agreeing to talks about talks increase if it appears that the position on preconditions of these other countries, particularly the United States and China, has changed," said Joel Wit, an expert on the North Korean nuclear issue.

The No.1 U.S. precondition for resuming six-party talks has been that the North should stop all nuclear activity to demonstrate its commitment to give up its nuclear programs, and Wit said the demand is too high for the North.

"There is a serious problem with the precondition position unless it's been modified," he said. "They can't stop everything and even if they said they stopped everything, your next question is, how do you know they stopped everything?"

Wit said China had attempted to bridge the gap in precondition positions between the U.S. and North Korea, but was unable to do so.

"I think the key issue here is whether there is any signs of flexibility on the part of the United States," Wit said.

The six-party talks have been stalled since late 2008. Since then, the North has bolstered its nuclear capabilities and stockpile and conducted its second and third nuclear tests, in 2009 and 2013. Some experts now warn that the communist nation's nuclear arsenal could expand to 100 bombs by 2020. (Yonhap)