Tillerson said Tuesday that the US was "ready to talk anytime North Korea would like to talk" and willing to have the first meeting "without precondition."

"Let's just meet. We can talk about the weather if you want," he told a forum at the Atlantic Council think tank.

It was widely interpreted as a departure from US demands that North Korea first halt its nuclear and missile testing and demonstrate its sincerity about denuclearization.

Just two weeks earlier, the communist regime test-launched an intercontinental ballistic missile it claimed was capable of carrying a nuclear weapon to all parts of the US mainland.

That initially dashed hopes for a resumption of dialogue between Washington and Pyongyang, which had sprung out of a 75-day pause in provocations from the North. US officials had said a pause of 60 days would send a signal of Pyongyang's interest in talks.

"I think Secretary Tillerson's remarks could have been potentially helpful because they would have clarified publicly that the US is willing to engage with North Korea without preconditions," said Frank Aum, senior expert on North Korea for the US Institute of Peace.

"Making this statement publicly also would have put the US on the high ground and put the ball back in North Korea's court, giving them the responsibility of accepting or rejecting a peaceful overture," said Aum, a contributor to 38 North, a North Korea monitoring website.

But the White House was terse. In a statement, it said the president's views on North Korea "have not changed."

It "seemed to undercut Tillerson's message and, even worse, undermined Tillerson as the nation's top diplomat," according to Aum.

Robert Manning, a senior fellow at the Atlantic Council, offered his interpretation: "I suspect Trump may have been irked that anyone was getting attention other than himself."

The current US policy of "maximum pressure" through sanctions and diplomatic isolation will probably continue, but the tactics may become more flexible, he added.

Pak was more concerned about the "mixed messaging" from the Trump administration.

That "undermines US credibility and creates conditions for a miscalculation that could lead to an unintended conflict," she said. (Yonhap)