On the call, which lasted less than 30 minutes, Trump sought Moon’s interpretation of Pyongyang’s shift to a harder-line position last week, a sharp contrast to the more positive and constructive tone after Moon met with North Korean dictator Kim Jong Un last month, according to a senior U.S. official with knowledge of the conversation…

National security adviser John Bolton has been telling colleagues that he doesn’t trust that the summit will go well, and he has reiterated his long-standing belief that he does not trust the North Koreans, a different person familiar with his views said.

Aides emphasized that Trump remains committed to meeting with Kim and that planning is moving forward but that time is running out to nail down an agenda and finalize several outstanding issues. The senior U.S. official said Pyongyang appears to be trying to extract more concessions from the United States before the summit, or to be building a narrative to blame Trump if things go poorly in Singapore or to pull out of the summit entirely.