Iran’s recent failed ballistic missile launch from a submerged “midget” submarine has once again drawn attention to Iran’s military ties with another of America’s most outspoken opponents, North Korea.

The failed missile test is said to have been Iran’s first with the Jask-2 underwater cruise missile, a missile design intelligence experts believe to be a copy of previous missiles tested in North Korea.  Such a revelation would hardly be a surprise, as the Ghadir class electric submarine used as a platform to launch the cruise missile is also a direct copy of the North Korean Yono class sub.

The similarities in Iran’s ballistic missile progress and North Korea’s are a bit too much to be considered coincidence, despite Iran’s agreement to end their pursuit of nuclear weapons.

“The very first missiles we saw in Iran were simply copies of North Korean missiles,” said Jeffrey Lewis, a missile proliferation expert at the Middlebury Institute of International Studies at Monterey. “Over the years, we’ve seen photographs of North Korean and Iranian officials in each other’s countries, and we’ve seen all kinds of common hardware.”

Another Iranian missile test conducted earlier this year was said to be based on a North Korean design, and last year Iran was seen testing a missile very similar in design to the Kim regime’s Musudan missile: North Korea’s most advanced platform successfully tested to date.  Iran’s Shahab missile also bears a striking resemblance to North Korea’s Taepodong design.

“In the past, we would see things in North Korea and they would show up in Iran. In some recent years, we’ve seen some small things appear in Iran first and then show up in North Korea and so that raises the question of whether trade — which started off as North Korea to Iran — has started to reverse,” Lewis added.

North Korea’s ballistic missile program is based on a submarine-launch capable design, and they saw their first successful launch from a submerged vessel in 2015.  Despite the failure of Iran’s most recent test, experts believe it’s likely that Tehran isn’t far from accomplishing a similar feat.

Submarine-based ballistic missiles present a distinct problem in the hands of the Iranians, who have demonstrated aggressive behavior toward the American Navy repeatedly as they traverse the narrow and strategically important Strait of Hormuz, which separates the Persian Gulf from the open ocean.