North Korea understands that international inspectors need to be present for verification when it dismantles its main nuclear complex in Yongbyon, the U.S. State Department said Thursday.

"Having IAEA inspectors and United States inspectors be a part of anything is really just a shared understanding," department spokeswoman Heather Nauert said at a press briefing, in reference to the International Atomic Energy Agency.

Nauert made the remark a day after North Korean leader Kim Jong Un, in a joint declaration with South Korean President Moon Jae In, expressed willingness to permanently dismantle Yongbyon, but without any explicit mention of expert international oversight.

In comparison, Kim pledged to permanently dismantle the North's key missile test site in Tongchang-ri "under the observation of experts from relevant countries," according to the declaration issued after the two-day inter-Korean summit in Pyongyang.

(A TV report on the dismantlement of N. Korean nuclear test site in May)

Asked about the difference, Nauert stressed that Washington, Pyongyang and Seoul, understand the importance of verifiable denuclearization.

"Anytime you have a nuclear situation like this, where there is a dismantlement, the expectation is that IAEA inspectors would be a part of that," she said. "So that would just be a normal course of doing business."