Nauert said behind-the-scenes discussions with Pyongyang have normalized in the wake of President Donald Trump's June summit with North Korean leader Kim Jong Un and subsequent meetings between US Secretary of State Mike Pompeo and other top Pyongyang officials.

"We consider meetings, negotiations, conversations as we move forward behind the scenes with those negotiations to be moving in the right direction," Nauert said in a press briefing.

"Conversations with the government of North Korea are becoming a far more normal matter."

The comments came after North and South Korea announced Monday that they had agreed to hold a summit in Pyongyang in September.

Nauert would not provide details of the talks -- where they were taking place, who is involved, or what issues are currently under discussion.

But she reiterated the US view that Kim told Trump he was willing to denuclearize, which is the primary US goal of the discussions.

She noted North Korea's recent release of the remains of US servicemen who died during the Korean War in the early 1950s as a sign of progress.

"That is certainly a step in the right direction," she said.

"We continue to have those conversations because Chairman Kim has committed to President Trump that they are willing to denuclearize. And so we will continue in a full good faith effort to have those conversations move forward."