A senior U.S. State Department official will visit Seoul soon to get a better grasp of inter-Korean economic cooperation.

Mark Lambert, a special representative for North Korean policy, is expected to meet executives of South Korean businesses that have been involved in cross-border projects.

They will include firms that had workshops in the joint Kaesong Industrial Complex, Hyundai Asan, which used to run package tours to Mt. Kumgang in North Korea, as well as KORAIL and KT.

"Lambert will listen to executives of South Korean companies about their involvement in cross-border economic projects and determine whether they violate sanctions imposed by the UN Security Council and the U.S.," a diplomatic source said.