A new ISIS video purports to show weapons airdropped by U.S. forces intended for Kurdish fighters in the hands of the very militants the munitions were meant to destroy.

The U.S. on Sunday said it had dropped weapons, ammunition and medical supplies for the first time to Kurdish fighters defending the Syrian town of Kobani from ISIS. A day later, U.S. officials said one of the six airstrikes it carried out near Kobani intentionally struck a bundle of supplies to keep it from falling into the wrong hands.

ISIS propaganda material in the past has shown fighters flaunting what appear to be U.S.-made weapons, tanks and Humvees seized from retreating Iraqi forces.

Still, the seizure of emergency arms dropped by the U.S. for Kurdish forces would be a troubling development mixed with a dose of embarrassment for the American-led anti-ISIS coalition. One of the main sticking points against arming moderate rebels battling to unseat Syria’s President Bashar al-Assad was the idea weapons could fall into the wrong hands.

A new video released Tuesday by Aamaq News — an ISIS affiliated media unit — shows hand grenades and RPGs which a fighter in the video says were dropped from U.S. aircraft.

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Rifling through a crate, a fighter fiddles with rusty-looking munitions and explains “this is some of the military equipment that was dropped by American forces.” A box with metal cannisters is opened and the man cracks open the case: “These are the bombs that the American forces dropped for the Kurdish parties,” he says. “They are spoils of war for the Mujahideen.”

While the video could not be independently verified by NBC News, analysts and experts said it appeared likely the arms on display came from the U.S. airdrop. Pentagon spokesman Rear Admiral John Kirby told reporters Tuesday analysts were still analyzing the video, but the arms shown are the kind being dropped to Kurdish forces.

"So it's not out of the realm of the possible in that regard. But, again, we're taking a look at this, and we just don't know," Kirby said. "We are very confident that the vast majority of the bundles did end up in the right hands."

Reed Foster, head of the military capabilities desk at IHS Jane's, told NBC News that the video featured what appeared to be disassembled munitions from RPG-7 — probably sourced from an eastern European country — and an older type of DM41 fragmentary grenades of German origin.

“Unsurprisingly perhaps, many of these munitions are likely European in origin,” he explained. “Probably surplus stocks from NATO countries, which would potentially be much easier to procure … and fly them into theater than sourcing all the way from the U.S.”

A senior administration official told reporters earlier this week that the weapons dropped by the U.S. had been provided by Kurdish authorities, which would help explain the origins and why some of the weapons in appearing in the video appear aged and/or Soviet.

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— Ghazi Balkiz, Cassandra Vinograd and Courtney Kube