The launch was the latest North Korean rocket test to fall short of objectives, but still shows disturbing progress in its pursuit of the ability to deliver a nuclear warhead, according to U.S. officials and weapons experts. They said the mission could boost the regime’s ambitions and its standing among countries with similar goals.

Unlike North Korea’s 2006 test in which a Taepodong 2 rocket failed 40 seconds after launch, the rocket this time successfully went through the first two stages.

A senior Defense official said the military was now “clearly more worried” about the North’s missile technology. The senior official spoke on the condition of anonymity because the Pentagon did not authorize anyone to speak publicly about the launch…

“They are definitely collaborating with the Iranians,” said Obering, the former missile defense chief. “I would not be surprised if they didn’t have Iranians there.”