WASHINGTON — President Trump declared himself a “little disappointed” on Thursday by new evidence that North Korea was restoring a space-missile launch site, as a senior American official warned that a satellite launch would violate Kim Jong-un’s commitments toward halting his nuclear weapons program.
A week after a fruitless meeting in Vietnam with Mr. Kim, the North Korean leader, Mr. Trump attempted to avoid sounding very concerned about satellite evidence that Pyongyang was reactivating the launch site. Analysts believe that restoring the site is one of several steps Mr. Kim is taking to gain leverage in negotiations, as Mr. Trump demands a complete dismantlement of North Korea’s nuclear and missile programs.
In brief comments in the Oval Office, Mr. Trump told reporters that “we’ll let you know in about a year” whether his diplomacy in North Korea has been successful.
Last June, after his first meeting with Mr. Kim in Singapore, the president suggested that the success of the effort could be judged in six months.
But the diplomacy has stalled. And North Korea’s behavior — which may simply amount to signaling displeasure at Mr. Trump’s refusal to lift sanctions against Pyongyang in return for the dismantlement of its oldest nuclear site — suggests that the two countries may be reverting to their old playbook of threats and counterthreats.
The Trump administration’s patience with the North Korean program stands in sharp contrast to far more specific warnings it gave when Iran was preparing to launch a similar space mission. The seemingly civilian space missions are considered to be proxies for a missile launch; much of the technology needed to cast a satellite in space is the same as launching a warhead.
The space facility in North Korea is called Sohae, and Mr. Kim promised Mr. Trump in Singapore that it would be dismantled. But preliminary work to take it apart halted in the fall.
On Thursday, a research team at the Center for Strategic and International Studies said the most recent activities at the Sohae site “amount to a ‘snapback’ from the moderate dismantlement undertaken by the North Koreans” last year.
The authors of the report — Victor Cha, a former George W. Bush administration national security official whom Mr. Trump considered for American ambassador to Seoul, and Joseph Bermudez, a longtime interpreter of satellite imagery over North Korea — said the images show how easy it is for the North to “reverse steps it might take toward denuclearization in the future.”
So far, however, there has been no missile on the launchpad at Sohae, nor an indication that one will be sent into space.
At the State Department, the senior administration official said the United States had not concluded whether North Korea was intending to conduct a launch. But that would amount to backsliding on commitments made to Mr. Trump, the official told reporters in a briefing, where he insisted on anonymity to discuss the sensitive diplomacy.
In fact, Mr. Kim appears to have backtracked on several of those commitments. Sohae was never dismantled, and inspectors were never allowed in.
Similarly, North Korean officials told Secretary of State Mike Pompeo during a visit to Pyongyang last fall that they would allow international inspectors into a nuclear testing site that they said had been sealed after its entrances were blown up. The inspectors have never been permitted into the country.
While Mr. Trump and his staff have done everything they can to avoid directly criticizing Mr. Kim or imperiling negotiations, administration officials said they knew it would be impossible to ignore, or explain away, a space mission.
When Iran recently attempted to launch its own satellite, the State Department issued a series of strongly worded warnings to Tehran. The mission failed, and there was some speculation about whether that failure was the result of an American-led sabotage program against the missiles. The United States ran a similar program during the Obama administration against North Korea.
Mr. Trump’s comments on North Korea were considerably softer than the warnings to Iran — a reflection of the care he takes not to alienate Mr. Kim, whom he has praised effusively.
But Mr. Kim never made any written commitments to dismantle the sites or give access to inspectors. North Korean officials also have argued that the United States has failed in its commitments to take steps to improve the relationship between the two countries, starting with the lifting of the most effective sanctions on its imports and exports.