U.S. weapons experts believe North Korea may be preparing to test a new strategic weapon system that would vastly expand Kim Jong Un’s arsenal and defy President Donald Trump’s threshold requirements for continued engagement with the U.S.

The experts, led by Dr. Victor Cha of the Center for Strategic and International Studies “Beyond Parallel” website, have posted new and unusually clear satellite images taken Friday that show North Korea may be preparing its first submarine-launched ballistic missile test, potentially a major new development for the North.

The experts say the pictures show a submersible test stand barge at the Sinpo South Shipyard.

According to the “Beyond Parallel” assessment, the primary indicator suggesting preparations for a test launch is the presence of several vessels within the boat basin, one of which resembling ships used to tow the test barge out to sea. Another indicator is two Romeo-class submarines anchored within the base that experts say could be used as escorts for an SLBM test maneuver.

“This looks like they are certainly preparing to do an SLBM test for the first time,” said Cha, an NBC News contributor on Asian Affairs. “Kim Jong Un has been talking about unveiling a new strategic weapon and this may be it. There’s been a lot of activity around this one site where the test barge is located.”

Since the failed Hanoi Summit between President Trump and Kim in February 2019, Trump has dismissed a series of short-range, land-based missile tests as not threatening the United States, although they do violate United Nations Security Council resolutions.

“A sea-launched missile test would definitely cross all of President Trump’s red lines because it would involve a major ballistic missile,” Cha said. “It would be difficult for President Trump to ignore this.”

The experts believe the earliest North Korea would be ready to launch would be September 8th in the U.S. — which would be September 9th in North Korea. That is North Korea’s Foundation Day, honoring the establishment of the state.

In the past, Kim has liked to test new weapons on his country’s holidays, as well as ours, to get maximum attention. Launching the test only months before the U.S. election would raise a major political challenge to the President’s claim of progress with the North as one of his diplomatic achievements.