An intermediate-range ballistic missile launched by North Korea back in April accidentally struck a North Korean town, causing an explosion and possibly casualties, according to a report in the Diplomats.

The news comes after North Korean leader Kim Jong Un agreed to reopen a hotline between North and South Korea, allowing them to resume talks ahead of the Olympic games.

What happens when a North Korean ballistic missile test fails in flight and explodes in a populated area? On April 28, 2017, North Korea launched a single Hwasong-12/KN17 intermediate-range ballistic missile (IRBM) from Pukchang Airfield in South Pyongan Province (the Korean People’s Army’s Air and Anti-Air Force Unit 447 in Ryongak-dong, Sunchon City, to be more precise). That missile failed shortly after launch and crashed in the Chongsin-dong, in North Korean city of Tokchon, causing considerable damage to a complex of industrial or agricultural buildings. According to a U.S. government source with knowledge of North Korea’s weapons programs who spoke to The Diplomat, the missile’s first stage engines failed after approximately one minute of powered flight, resulting in catastrophic failure. The missile never flew higher than approximately 70 kilometers. The location of the missile’s eventual impact was revealed exclusively to The Diplomat and evidence of the incident can be independently corroborated in commercially available satellite imagery from April and May 2017.

It's rumored that US special operations forces were responsible for the missile launch failures. The secretive regime makes it nearly impossible to determine the extent of damages. If a missile were to strike a populated area, the result would be catastrophic.

From an area near the Pukchang Airfield, the missile flew approximately 39 km to the northeast where it struck a complex in the small city of Tokchon seen below. Had it completed its flight successfully, the missile may have been designed to land in the northern reaches of the Sea of Japan, near the Russian coast. North Korea used a similar splashdown location for its first successful Hwasong-12 flight-test in May 2017. (The launch, however, took place from Kusong, not Pukchang.)

Satellite images of the impact point show a crater where a large structure once stood:

An image from Google earth of the complex show ground disturbances in an area that previously contained a building with fencing, also showing that a portion of the seasonal greenhouse had been damaged near the side of the complex where the debris fell. Using Planet Labs’ high frequency satellite images of this site, we can narrow down the date which this change occurred, which was sometime between the 26th and the 29th, or the two-day window in which the test is known to have occurred.

Liquid-fuel missiles like the Hwasong-12, which use a highly volatile combination of hypergolic propellant and oxidizer (meaning that the two agents ignite spontaneously on contact), can cause a massive explosion if the fall in just the right manner.

In this case, with the missile having survived its descent following an engine failure, it is likely that the impact of the missile destroyed the facility at Tokchon where the blast is believed to have occurred. It’s impossible to verify if the incident caused any loss of life and, given the time of day the test occurred and the location of the impact, it may be likely that few, if any, casualties resulted from the incident.

North Korea successfully launched its first flight-test of the IRBM on May 14, 2017, firing the missile into the ocean. The country caused alarm when they test-launched missiles over Japanese territory in August and September, though the missiles landed in the Pacific Ocean outside of Japanese territory.