South Korean nuclear envoy Noh Kyu-duk is due to meet on Monday in Washington with his American counterpart Sung Kim to discuss North Korea issues.
They last met around two weeks ago in Jakarta.
Their discussions are expected to include the North's recent missile launches and the resumption of talks with the regime.
They've also been talking about how to provide the North with humanitarian aid.
On Tuesday, Noh will meet with both his U.S. and Japanese counterparts.
And today in Seoul, South Korea's intelligence agency chief Park Jie-won reportedly met behind closed doors with his U.S. counterpart Avril Haines and Japan's cabinet intelligence director Hiroaki Takizawa.
They too are likely to have discussed ways to bring the North back to talks.