– Kim Jong Un oversaw a live-fire military exercise Saturday that potentially included North Korea’s first ballistic missile launch since 2017 — challenging U.S. President Donald Trump’s bottom line in nuclear talks.

Kim watched as “large-caliber, long-range multiple-rocket launchers and tactical guided weapons” were fired off North Korea’s eastern coast Saturday, according to the official Korean Central News Agency. The state media report Sunday was accompanied by a photo of what nonproliferation analysts said appeared to be the launch of a short-range ballistic missile.

Such a test would violate U.N. resolutions imposing sanctions on North Korea but would stop short of breaching Kim’s own pledge to refrain from testing longer-range missiles to threaten the U.S. Trump had earlier brushed off the incident, tweeting Saturday that Kim “does not want to break his promise to me.”

“Kim Jong Un may be starting his ‘push-the-line’ strategy, gradually seeing how much Trump will turn a blind eye to,” said Vipin Narang, an associate professor of political science at the Massachusetts Institute of Technology. “Not good.”

Neither U.S. nor South Korean authorities immediately confirmed a ballistic missile launch, which was bolstered by a satellite image from Planet Labs Inc. showing what appeared to be a single missile contrail at the exercise site. South Korea’s defense ministry said that North Korea tested “new tactical weapons” and artillery that traveled 40 to 150 miles, without mentioning “missiles.”

Nathan Hunt, an independent defense researcher, said the South Korean statement was “skirting over” the North’s ballistic missile launch. “They did indeed test a new short-range missile, or as others call close-range ballistic missile, and this was not just an artillery drill,” Hunt said.

Either way, the exercise was Kim’s most significant provocation since he launched an intercontinental ballistic missile in November 2017, declared his nuclear weapons program “complete” and opened talks.

Kim has expressed frustration since Trump refused his demands for sanctions relief and walked out of their second summit in February.

The North Korean leader accused the U.S. of “bad faith” during a meeting with Russian President Vladimir Putin in Vladivostok last month. He had earlier told North Korea’s Supreme People’s Assembly that he would wait “with patience till the end of this year” for the U.S. to make a better offer.

Analysts said the weapon featured in the KCNA photograph appeared to be a solid-fuel ballistic missile similar to a Russian Iskander that could be stored while fueled, deployed and fired with less detection time. North Korea had put a similar weapon on display during a military parade in February 2018.