"There is currently no firm date for the return of international staff to Pyongyang, but discussions are continuing on timing and modalities," said a spokesperson for the office of Joe Colombano, the U.N. resident coordinator for North Korea.
But analysts suggest Washington may be open to resuming talks with North Korea, with Moscow potentially playing the role of mediator.
South Korea relies on security guarantees from the US to deter North Korean aggression, providing sites that host about 28,500 American troops. Earlier in March, a nuclear-powered US aircraft carrier docked at a South Korean port, prompting the sister of North Korean leader Kim Jong Un to denounce the deployment of strategic assets in the region.
South Korea's humanitarian assistance to North Korea reached zero last year for the first time in nearly 30 years, amid Pyongyang's continued antagonistic stance toward Seoul, the unification ministry said Wednesday.