The United States pointedly showed off its military prowess over the Pacific and the Korean Peninsula on Sunday in response to North Korea’s launch Friday of a missile capable of reaching the U.S. mainland, a test Pyongyang said was a “stern warning” for Washington to back off from threats and more sanctions.

In a sign that tensions are spiraling upward rapidly, the United States flew two supersonic B-1 bombers over the Korean Peninsula as part of a joint exercise with Japan and South Korea. And U.S. forces conducted a successful missile defense test over the Pacific Ocean, sending aloft from Alaska a medium-range ballistic missile that it detected, tracked and intercepted using the Terminal High Altitude Area Defense System.

[As North Korea intensifies missile program, U.S. opens $11 billion base in the South ]

The sense that time is running out in the confrontation with North Korea was reinforced as the day wore on. Nikki Haley, the U.S. ambassador to the United Nations, batted down rumors that the United States would seek an emergency meeting of the U.N. Security Council. It was pointless, she said, as long as China wouldn’t commit to increasing the pressure on North Korea’s leader, Kim Jong Un.

“In fact, it is worse than nothing, because it sends the message to the North Korean dictator that the international community is unwilling to seriously challenge him,” said Haley, who earlier retweeted a photo of the bombers on their mission over the Korean Peninsula. “China must decide whether it is finally willing to take this vital step. The time for talk is over.”

(Reuters)

The basic dilemma for the United States is that North Korea’s missile technology has leapt forward faster than predicted, leaving few realistic options for a resolution, which can take time to negotiate.

“Kim Jong Un is not going to negotiate in good faith,” said Cliff Kupchan, chairman of the Eurasia Group, a political risk consulting firm. “He sees acquisition of a nuclear deterrent as critical to his country’s security. The U.S. is on the verge of a binary choice: either accept North Korea into the nuclear club, or conduct a military strike that would entail enormous civilian casualties.”

Amid the show of force by the United States and its allies, North Korea said it would respond with a “resolute act of justice” if it were provoked either militarily or economically.

“In case the U.S. fails to come to its own senses and continues to resort to military adventure and ‘tough sanctions,’ the DPRK will respond with its resolute act of justice,” the state-run Korean Central News Agency quoted a Foreign Ministry spokesman saying, using the acronym for the North’s official name, the Democratic People’s Republic of Korea.

The spokesman said the United States should “wake up from the foolish dream of doing any harm to the DPRK,” and warned Washington against a preemptive nuclear strike.

“If the Yankees . . . dare brandish the nuclear stick on this land again . . . the DPRK will clearly teach them manners with the nuclear strategic force,” the spokesman said.

The Trump administration’s frustration has grown exponentially in recent days, since Pyongyang on Friday conducted its second successful test of an intercontinental ballistic missile. Though it landed off the Japanese coast, experts said if the missile had flown in a lower arc it could have reached the U.S. mainland.

A U.S. Air Force B-1B Lancer (top) assigned to the 9th Expeditionary Bomb Squadron, being joined by Republic of Korea air force F-15s, during a mission into Japanese airspace and over the Korean Peninsula. American forces on July 30 successfully tried out a missile interception system the U.S. hopes to set up on the Korean peninsula. (Kamaile Casillas/Air Force via AFP/Getty Images)

U.S. officials have been trying to get China, North Korea’s main trading partner and economic lifeline, to exert pressure on its neighbor. Secretary of State Rex Tillerson has called Beijing and Moscow the “principal economic enablers” of Pyongyang. Though China voted last year for harsh U.N. sanctions against the country’s leaders and state-tied companies, it fears that a destabilized regime would send refugees flooding across the border and has urged dialogue as the only pragmatic approach.

President Trump on Saturday berated China, tweeting that “they do NOTHING for us with North Korea, just talk. We will no longer allow this to continue.” And Vice President Pence, traveling Sunday in Estonia, told reporters that “all options are on the table.”

“The continued provocations by the rogue regime in North Korea are unacceptable, and the United States of America is going to continue to marshal the support of nations across the region and across the world to further isolate North Korea economically and diplomatically,” Pence said.

North Korea tested its first nuclear weapon in 2006 and has been burdened with six sets of U.N. sanctions since then. The North claims its weapons are for defensive purposes. But a series of missile launches and tests conducted since Kim came to power more than five years ago have increased concern that North Korea may be closing in on the ability to fit a nuclear weapon on a missile’s nose cone.

The North Korean leader himself had openly boasted that more missile tests would be coming. In late March, he vowed to send a “bigger gift package to the Yankees,” state-run media reported.

“People have been warning about the North Korean ICBM for 20 years,” Joseph Cirincione, president of the Ploughshares Fund, said Sunday on ABC’s “This Week.” “But the wolf is at the door. This a very real threat to the United States.”

Sen. Dianne Feinstein (D-Calif.), speaking on CBS’s “Face the Nation,” called North Korea a “clear and present danger” that must be taken seriously.

“I’m convinced that North Korea has never moved at the speed that this leader has to develop an ICBM to put solid fuel, to have an interesting launch device, and to have a trajectory which, as of the latest analysis, would enable it to go about 6,000 miles and maybe even hit as far east as Chicago,” she said. “We can’t have that.”

Feinstein said she hoped John F. Kelly, the incoming White House chief of staff who starts his new position Monday, would be able to begin negotiations with Pyongyang that would eventually end its nuclear program.

For now, however, worried capitals are focusing on bulking up their militaries. South Korea announced Saturday that it will start talks with the White House about building more powerful ballistic missiles capable of striking the North.

[South Korea, in a shift, wants more military firepower against the North]

And the U.S. military was blunt in its assessment of the threat posed by North Korea. In a statement accompanying the departure of the two B-1 bombers from Guam to the Korean Peninsula, the Pacific Air Forces commander, Gen. Terrence J. O’Shaughnessy, called the country the “most urgent threat to regional stability.”

“If called upon, we are ready to respond with rapid, lethal, and overwhelming force at a time and place of our choosing,” he said.

Ashley Parker and Madhumita Murgia contributed to this report.