Secretary of State Rex Tillerson, left, and Secretary of Defense Jim Mattis hold a news conference with their Japanese counterparts at the State Department that largely focused on North Korea. (Shawn Thew/EPA)

The top U.S. diplomat and top defense official moved again Thursday to clarify the Trump administration’s North Korea policy, making clear that it is focused on diplomatic and economic pressure, and that American military action is currently contemplated only in response to an attack by Pyongyang.

“In close collaboration with our allies, there are strong military consequences if DPRK initiates hostilities,” Defense Secretary Jim Mattis said, using the initials of the Democratic People’s Republic of Korea. “Very simply, in the event of a missile launch toward the territory of Japan, Guam, the United States, [South] Korea, we would take immediate specific actions to take it down.”

His remarks fell between President’s Trump’s warning last week that the United States was prepared to respond militarily to Pyongyang’s “threats” of an attack, and this week’s remark by White House chief strategist Stephen K. Bannon that North Korea was a “sideshow” to which there was “no military solution.”

In the whirlwind of successive controversies and crises that have become the hallmark of the Trump administration, domestic strife in Charlottesville has quickly overtaken last week’s worry about war with North Korea.

But even as attention has rapidly shifted at home, partners in East Asia and beyond have continued to seek reassurance that the United States will defend them as vigorously as it will protect itself, if necessary, while refraining from initiating a shooting war on its own.

In Seoul on Thursday, South Korean President Moon Jae-in said he had received assurances from visiting Gen. Joseph F. Dunford Jr., chairman of the Joint Chiefs of Staff, that the United States would take no military action against North Korea without first getting his government’s agreement.

Dunford said that there was “no question” Seoul would be consulted and that “everything we do in the region is in the context of our alliance.”

In Washington, Mattis spoke alongside Secretary of State Rex Tillerson, at a news conference with their Japanese counterparts, following a bilateral security meeting. Along with Dunford, they have repeatedly tried to inject calm and a sense of strategy into differing administration messages that have unsettled allies and the American public.

Contributing to the concern was Trump’s national security adviser, H.R. McMaster, who this month told a group of current and former senior U.S. national security officials and foreign policy experts that “preventive” war with North Korea was one of the “viable” military options under consideration.

The term is sometimes used interchangeably with “preemptive” action, although the latter refers more often to forestalling an imminent attack. Japan’s 1941 bombing of U.S. ships docked at Pearl Harbor is widely considered the classic example of a preventive operation.

McMaster, in an earlier interview broadcast on MSNBC, said that Pyongyang’s possession of nuclear weapons capable of attacking the United States was “intolerable, from the president’s perspective” and that military options for eliminating that threat were being provided.

Vice President Pence, on a visit this week to Chile, said that “all options are on the table” regarding North Korea. Although there were “glimmers of hope” that nonmilitary pressure would make a difference, Pence said that the United States would “simply not permit” Pyongyang “to possess usable nuclear weapons that can reach the continental United States.”

The sense of imminent military conflict began to escalate last month, when North Korea conducted two test launches of intercontinental ballistic missiles that put “the whole U.S. mainland” within Pyongyang’s reach, according to North Korean leader Kim Jong Un. Later reports said that U.S. intelligence officials had concluded that Pyongyang had successfully miniaturized nuclear warheads to mount on the missiles.

“We will handle North Korea. We are going to be able to handle them,” Trump told reporters. On Twitter, he said he was “very disappointed” in China, Pyongyang’s primary economic partner. “They do NOTHING for us with North Korea, just talk. We will no longer allow this to continue.”

On Aug. 5, the U.N. Security Council voted unanimously in favor of a U.S.-drafted resolution imposing harsh new economic sanctions on North Korea. Over the next few days, Pyongyang said it would respond “ruthlessly” with “physical actions.” Trump said that “North Korea best not make any more threats,” or it would be “met with fire and fury and frankly power, the likes of which this world has never seen before.”

Pyongyang then upped the ante, saying it was considering a plan to launch missiles toward Guam. Trump tweeted that the U.S. military was “locked and loaded.”

Throughout the rhetorical escalation, Tillerson and Mattis have tried to lower the temperature without overtly disagreeing with Trump. They began this week with a joint opinion piece published by the Wall Street Journal, repeating that the United States sought denuclearization of the Korean Peninsula but was not trying to get rid of the government in Pyongyang.

On Monday, Mattis acknowledged that it would be “a wartime situation” if North Korea fired a missile toward Guam. “If they do that, then it’s game on,” he told reporters, indicating that such a missile would be shot down.

But “let’s not do this, okay folks? Let’s not start saying ‘General Mattis said it’s war.’ 

“We will defend the country — hear me, now — we will defend the country from any attack . . . at any time, from any quarter. . . . But it is not declaring war. It’s not that I’m over here, you know, Dr. Strangelove, you know, doing things like that, okay?”

The next day, North Korea’s state media said that Kim would put the Guam attack on hold and “watch a little longer” before deciding what to do. Trump, tweeting in response, called that “a very wise and well reasoned decision.”

Late Wednesday, Bannon’s comments appeared to have come out of left field. The administration, he said in an interview published by the American Prospect magazine, should give up trying to persuade China to clamp down on North Korea and should instead proceed with tough trade sanctions against Beijing.

“There’s no military solution [to North Korea’s nuclear threats], forget it,” Bannon said. “Until somebody solves the part of the equation that shows me that ten million people in Seoul don’t die in the first 30 minutes from conventional weapons, I don’t know what you’re talking about.” Bannon went on, the magazine reported, to describe a battle inside the administration over whether to go easy on China in what he considered the vain hope it would restrain Pyongyang.

Tillerson, on Thursday, declined to comment on Bannon’s remarks. “I think we have been quite clear as to what the policy and the posture toward North Korea is,” he said.

What he and Mattis want to do, he said, is to “inform the American people, first, but also inform our important friends and allies as to what our approach is.”

That approach — diplomatic and economic pressure, with military options ready if needed — is different from pressure campaigns under previous administrations, Tillerson said, because of “the level of international unity around this campaign, the level of cooperation we are getting from China and from others in the region.”

Trump, Tillerson said, “just felt it was necessary to remind the [North Korean] regime of what the consequences for them would be if they . . . make a bad choice for themselves.”

Carol Morello, Anne Gearan and Adam Entous in Washington and Anna Fifield in Seoul contributed to this report.