WASHINGTON – President Donald Trump and his national security advisers have repeatedly declined to criticize North Korea’s latest weapons tests, shrugging them off as small-scale and reiterating their desire to restart negotiations with Kim Jong Un.

"These missiles tests are not a violation of our signed Singapore agreement," Trump tweeted on Friday, referring to Kim's pledge last year to halt long-range missile and nuclear testing during their summit last summer.

"Chariman Kim has a great and beautiful vision for his country, and only the United States, with me as President, can make that vision come true," the president added. "He will do the right thing because he is far too smart not to, and he does not want to disappoint his friend, President Trump!"

That kind of response, some experts warn, is an open invitation for Kim to push the envelope when it comes to additional provocations.

“That’s a free pass given to North Korea, but it goes beyond that,” said Sung-Yon Lee, a Korean Studies professor at Tufts University's Fletcher School.

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“North Korea has routinized, has conditioned, the U.S. to accept these periodic short-range missile tests as a fact of life,” Lee said. And because the Trump administration has not condemned the tests, he said, Kim may ratchet up to intermediate or even long-range missiles.

North Korea has now conducted at least five weapons tests over the last three months, launching several short-range ballistic missiles in May and more in July. North Korea’s state media said its latest test, conducted earlier this week, was a new “large caliber” guided rocket system.

Although Trump and his advisers have publicly downplayed the tests, others in the administration have conceded they are troubling. A senior State Department official, speaking on the condition of anonymity under terms set by the administration, said the missile launches were “unwelcome” and counterproductive, particularly in light of North Korea's delay in restarting negotiations.

“Obviously any kind of provocations are unwelcome in this environment,” said the State Department official. “There is a common view that this is a huge mistake and a self-inflicted damage on their own part.”

Indeed, while the short-range missile tests may not pose a direct threat to the U.S., they do to South Korea and potentially Japan as well – two vital American allies in the region. And European leaders denounced North Korea's actions.

"We reiterate our condemnation of such launches, which are violations of UN Security Council Resolutions," the United Kingdom, France and Germany said in a joint statement on Thursday. "We urge North Korea to take concrete steps towards its complete, verifiable and irreversible denuclearisation."

In his tweets on Friday, Trump said the tests "may be a United Nations violation but ... Chairman Kim does not want to disappoint me with a violation of trust."

“It’s very much under control," Trump told reporters Thursday. “Short-range missiles, we never made an agreement on that.”

Michael Fuchs, a former deputy assistant secretary of state for East Asian and Pacific affairs in the Obama administration, said Kim is testing Trump – and learning an important lesson from the president's muted response.

“This is part of the negotiations, and I think that (Kim) is learning … that he can get away with this because President Trump has made it so clear, so publicly, in so many ways how invested he is in this process as a success,” said Fuchs, now a foreign policy expert with the liberal Center for American Progress. "The fact that North Korea hasn’t actually given up anything yet, the fact that North Korea is resuming missile testing, all gets in the way of the success narrative Trump wants to build.”

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Trump met Kim last month at the demilitarized zone separating North and South Korea – his third face-to-face summit with the dictator after an initial summit in Singapore last year and a meeting in Hanoi in February.

In Singapore, Trump and Kim signed a vague agreement to work toward the full denuclearization of the Korean Peninsula. But Kim has not taken any concrete steps toward relinquishing his nuclear arsenal, and the second round of talks in Hanoi collapsed after Kim asked for sweeping sanctions relief in exchange for partial denuclearization.

Trump hailed the DMZ meeting in June as historic and "legendary." But that event, while dramatic, did not produce any breakthroughs. Instead, Trump and Kim agreed only to set up negotiating teams aimed at restarting talks to dismantle North Korea's nuclear weapons programs.

And that has not happened.

Secretary of State Mike Pompeo hoped North Korea would send its foreign minister to Bangkok this week, where the American diplomat was participating in a meeting of Southeast Asian nations.

"I wish they had gotten here," Pompeo said Thursday in Bangkok. Asked about the missile tests, he said the "diplomatic path is often fraught with bumps ... We are still fully committed to achieving the outcome that we've laid out."

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Kim has not named any negotiators or agreed to any specific timeline for those talks.

North Korean state media has portrayed the country's recent missile tests as a “solemn warning” to protest planned joint military exercises scheduled next month. Those U.S.-South Korea exercises have been scaled back to be less provocative, but Kim’s regime has suggested the U.S. is “reneging” on its agreement to halt such activities.

Lee and others said that's not the real reason Kim has been testing new weapons.

“These exercises are non-threatening, mostly computer-simulated, and they’ve been going on for the past 40 years – literally since 1978,” Lee said.

They offer Kim a “pretext” to test weapons, which is actually driven by technical needs in North Korea’s development process and a desire to gain leverage if and when the talks do restart, said Scott Snyder, director of U.S.-Korea policy at the Council on Foreign Relations, a foreign policy think tank.

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“It’s pretty clear they’re trying to shape the environment for those talks,” he said.

Fuchs agreed that Kim is “trying to use this to put pressure on both South Korea and the United States.”

"Part of his tactic here is to keep everything, as much as possible, in negotiations with Trump himself,” Fuchs said. “And to continue to buy as much leverage and time as he can to get what he thinks is a good deal out of the guy at the top.”