Seoul's top nuclear envoy Lee Do-hoon said Thursday that South Korea and the United States have agreed to closely coordinate on possible inter-Korean cooperation projects.

Lee made the remarks to reporters after holding talks with his U.S. counterpart, Deputy Secretary of State Stephen Biegun, in Washington.

Asked about Biegun's response to individual tours to North Korea, Lee said that he explained the matter fully in the meeting and they plan to continue consultations.

While refusing to expand on what was said about the matter, Lee said that Washington has always expressed respect for decisions South Korea makes as a sovereign nation.

He added that it's important that South Korea and the U.S. work hard together and coordinate with each other as allies on the basis of that respect.

Lee explained that although individual tours are not subject to sanctions, they could raise "minor issues" in terms of what items tourists are allowed to bring to North Korea.