The move comes amid rapid rapprochement between the Koreas, sparking concern in the US that the delivery of supplies to the North could undermine sanctions placed on the regime for its nuclear weapons and ballistic missile programs.

"Our position has not changed," Katina Adams, the spokesperson for the US State Department, said in response to a Yonhap query.

"The United States and our allies the Republic of Korea and Japan are committed to close coordination on our unified response to North Korea. We expect all member states to fully implement UN sanctions, including sectoral goods banned under UN Security Council resolutions, and expect all nations to take their responsibilities seriously to help end the DPRK's illegal nuclear and missile programs."

DPRK stands for North Korea's official name, the Democratic People's Republic of Korea.

Seoul and Washington are in talks to clear any hurdles ahead of the ceremony.

Speaking to reporters in Washington on Tuesday, a senior South Korean government official said the talks are "going well" and that he expects "good news." (Yonhap)