South Korea's presidential office says that contact between the U.S and North Korea to prepare for their upcoming summit is going well. 

A senior presidential official told reporters on Monday that as far as the top office knows, the U.S.-North Korea contact is proceeding smoothly. 

The official said that National Security Adviser Chung Eui-yong is expected to contact his U.S. counterpart John Bolton soon. Bolton is set to take office on Monday. 

CNN reported on Sunday that the U.S. and North Korea have been holding secret, direct talks to prepare for the summit. 

CNN said that Central Intelligence Agency Director Mike Pompeo, tapped as Trump's new secretary of state, has been working through intelligence back-channels to prepare for the summit.

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