A former top U.S. security official said Sunday that President Donald Trump's tough rhetoric on North Korea also targets other countries in the region as he pursues a "sophisticated strategy" to address the nuclear standoff. 

During an interview with the local media, Stephen John Hadley, national security advisor for former President George W. Bush, said that Trump's volley of Twitter messages appear intended to address security concerns of America's allies, South Korea and Japan, and prod China into doing more to rein in the wayward regime.

A feisty Trump has turned to Twitter to excoriate Pyongyang for its provocations and express his frustration at hitherto unfruitful dialogue approaches to its denuclearization, triggering a flurry of speculation, including a possible military option.

"President Trump wanted to make it clear that he understood (South Korea and Japan's) anxiety, and that this was a serious problem not just for us, but for you in the region," said Hadley, currently a senior member of the U.S.-based think tank Atlantic Council. 

And he wanted to send a strong message to China that this issue could not be ignored, that the period of strategic patience was over and that the issue needed to be addressed in a serious way," he added.

Hadley was in Seoul to lead the Atlantic Council's delegation  as it met South Korean officials, including Foreign Minister Kang yung-wha, to discuss a range of issues such as North Korean threats and Trump's visit to Seoul, which is slated for Nov. 7-8.

Speaking of the possibility of Trump using a military option against North Korea, Hadley stressed Washington's priority is to use diplomacy. But he noted that a "prudent planner" would develop military options, as Seoul and Washington have done for decades to defend themselves against Pyongyang.

"One of the things you would do as a prudent planner is to develop some military options if North Korea were to be so foolish as to suggest that it was going to use its capability, whether against the United States, South Korea or Japan," he said. "So you would expect as a matter of prudent planning that our military and your military will be talking about military options.

But (Defense Secretary) General Mattis made it very clear that's not where we want to be," he added.

Hadley also dismissed the lingering speculation about dissonance between the White House and State Department on the North Korean issue, saying their public statements could look different but are part of an "integrated" message.

American diplomats, including Secretary of State Rex Tillerson, have talked of a diplomatic solution, but Trump has shown his aversion to dialogue-centric approaches, tweeting, "Talking is not the answer."  

"At the very essence of the strategy is pressuring, but also recognizing that there will be engagement at some point in terms of negotiations, and those two things sometimes are seen in opposition, but in fact, they are parts of a successful strategy," he said.

"I would say to you, understand that the message is going to seem mixed because it has both the pressure piece but also the opportunity for the resolution piece," he added.

Hadley also sought to dispel the speculation that Seoul and Washington may not be on the same page in tackling the issue, as South Korean President Moon Jae-in's inclination toward dialogue is seemingly at odds with Trump's hard-line stance.

"There are differences of tactics, I am sure that (is) always the case you have when you deal with a difficult, challenging problem," he said. "But I think we have been convinced and impressed by how much commonality and solidarity there is between the United States and South Korea."  (Yonhap)