It was a bizarre discovery: Customs officials find containers loaded with Soviet-era weapon parts hidden under bags of sugar on a North Korean-flagged freighter trying to pass through the Panama Canal.
In a state television broadcast, Cuba announced it owns the parts, which Havana says include obsolete anti-aircraft missiles, radar and warplane components that were going to North Korea for repair.
But one big question remains. Why would Cuba bother sending seemingly useless items to North Korea for repair?
"All we know is basically we have a North Korean ship with a lot of raw sugar, obsolete anti-aircraft missiles and radar equipment, and some spare aircraft engines bound for North Korea," said Tim Brown, a Senior Fellow at GlobalSecurity.org. "And we don't know whether the North Koreans are going to repair it or if it was going to be for sale, barter or what."
Although it could be weeks or months before it is known exactly what the cargo is, Panamanian Security Minister Jose Raul Mulino says has roused the interest of U.S. officials and international agencies.
"The United States has confirmed they will be sending an entire team, and the foreign ministry informed me that a visit of the United Nations experts has been scheduled in Panama for August the 5th to verify the weapons," he said.
Beyond their shared ideological adversity to the United States, Pyongyang and Havana have no history — at least none that is public — of any significant military cooperation.
"You have two ailing Stalinist regimes, the only two that are basically left in the world, and the only ones able to communicate with each other and deal with each other doing what would normally be considered just a nonsensical deal," said Brown.
It is because the case appears to make so little sense that intelligence analysts are working to learn more.
One possible explantion for the shipment that is being evaluated: whether North Korea is building a new relationship halfway around the world with Cuba. North Korea's isolation has been growing as traditional ally China raises pressure on Pyongyang.
"It's still to be determined what the Cubans were trying to get out of this, what the North Koreans were getting out of this," said Brown. "Why they would go to these lengths and risk this to achieve such very, very little benefit? If anything, it shows the desperation of the North Koreans."
U.S. officials have been cautious in their response, saying little about the seizure.
The United States considers Cuba an enemy government, but not an existential threat. The Obama administration has been taking steps to improve relations that have been frozen for more than a half century, and Cuba wants the U.S. economic embargo lifted.
The revelation of the illegal arms shipment and findings of further investigations may determine whether efforts to improve relations will go forward.