"North Korea has just launched another missile. Does this guy have anything better to do with his life?" Trump asked in a message very shortly after the launch yesterday.
"Hard to believe that South Korea and Japan will put up with this much longer," Trump continued. "Perhaps China will put a heavy move on North Korea and end this nonsense once and for all!"
The launch follows a string of recent actions by Pyongyang, including a salvo of missiles last month and three tests in May. Kim has now launched more missiles in one year than his father and predecessor in the family dynasty did in 17 years in power.
North Korea has also conducted five nuclear weapons tests since 2006, including two last year.
The number and variety of tests worry experts who see each step as part of a march toward a missile capable of striking America's West Coast.
The missile tests violate existing United Nations and other sanctions, which North Korea has found ways to evade. Although Trump and Secretary of State Rex Tillerson have declared that the "era of strategic patience" with North Korea is over, the new US Administration has not spelled out what that means.
Tillerson has said Washington might eventually negotiate with North Korea under the right circumstances, but he has suggested that possibility is remote. The United States will act alone if it must, he has warned, though he has not spelled out what exactly that would entail.
The Trump Administration has recently leaned on China to rein in North Korea and curb illicit trade with the country, an international pariah largely cut off from the global financial system.
Given that Japan and South Korea are within range of existing North Korean missiles, Trump has also sought to unite leaders of both nations behind a strongly worded US position that it will no longer tolerate the North's provocations. The Trump Administration has asked other nations around the globe to sever or downgrade diplomatic ties with Pyongyang.
Leaders of China, South Korea and Japan will be at the G-20 meeting in Germany.
Japanese Prime Minister Shinzo Abe appeared to share Trump's frustration, if not his tone. In remarks to the news media, he vowed to work closely with the United States and South Korea, but called on China and Russia to do more.
"I'd like to strongly urge international society's cooperation on the North Korea issue and urge China's chairman, Xi Jinping, and Russia's President Putin to take more constructive measures," Abe said.
In a daily news conference, Geng Shuang, a spokesman for China's Foreign Ministry, condemned the test but countered that Beijing had "spared no effort" in its fight.
Today, Russia and China jointly proposed that North Korea put further nuclear and missile tests on hold while the United States and ally South Korea refrain from large-scale military exercises. Both nations oppose North Korea's nuclear weapons programme. Both also oppose the US anti-missile system being installed in South Korea.
Experts said the Trump Administration does not have many choices for what to do next.
"Unfortunately, the Trump Administration has few options other than robust economic pressure on China and North Korea," said Anthony Ruggiero, a specialist on the long-running diplomatic and military standoff at the Foundation for Defence of Democracies.
"The US wasted the last 10 years with a combination of negotiations that were destined to fail and strategic patience that failed from the start."
A new sanctions regime led by the United States would be the best response, Ruggiero said, because China and Russia would veto the most effective form of sanctions at the UN Security Council.
Last week, the Trump Administration announced sanctions targeting a China-based bank accused of laundering money for the North Korean Government and moved forward with an arms sale to Taiwan that Beijing opposes.
Trump followed up with a call to China's Xi, in which Trump "raised the growing threat posed by North Korea's nuclear and ballistic missile programmes," according to the White House.
"Both leaders reaffirmed their commitment to a denuclearized Korean Peninsula," a White House statement said, while "President Trump reiterated his determination to seek more balanced trade relations with America's trading partners".
The trade reference was an implicit threat to reassert US complaints about Chinese economic practices that Trump has largely set aside in recent months as he has sought to engage Xi, with whom he claims a strong relationship.
China has pledged cooperation with the United States over North Korea but has not fundamentally shifted away from a strategy that balances pressure on the Kim regime with keeping the regime afloat, said Chris Steinitz, a research scientist at the federally funded, nonprofit Centre for Naval Analyses.
"It's kind of how China looks at everything. They have a very long view," Steinitz said. "They will wait, they will bide their time. They have a lot of priorities."
In the meantime, Steinitz said, North Korea will continue to test missiles.
The US military said the Hwasong-14 was in the air for 37 minutes, a duration that signals a significant improvement over previous tests. In a special announcement on state television, North Korea said the missile flew about 930km, reaching an altitude of 2800km.
The launch was made from a site in North Korea's North Pyongan province, and the missile flew more than 800km before landing in waters off Japan's coast, US, South Korean and Japanese officials said.
As with other recent launches, the missile appears to have been fired at a very steep trajectory in an effort to avoid flying over neighbours.
Multiple independent analyses of the test showed that the missile flew at a high-altitude trajectory, soaring to about 2735km before landing in the Pacific off the Japanese coast, about 930km from its launch point.
