A “very close” US ally used a $3 million Patriot missile to shoot down a quadcopter drone — which sells on Amazon for $200, according to reports.

“They shot it down with a Patriot missile,” Gen. David Perkins said in a video shared by the US Army on YouTube, the Independent of the UK reported. “Now that worked, they got it, OK, and we love Patriot missiles.”

The radar-guided Patriots travel at five times the speed of sound to bring down enemy missiles.

“That quadcopter that cost $200 from Amazon.com did not stand a chance against the Patriot,” Perkins said in describing the penny-wise and pound-foolish shootdown.

“I’m not sure that’s a good economic exchange ratio,” he added. “If I’m the enemy, I’m thinking, ‘Hey, I’m going to get on eBay and buy as many of these quadcopters as I can and expend all the Patriot missiles out there.’”

Perkins, who did not provide further details about the strike, said the unnamed country was “dealing with an adversary,” suggesting the incident was not a test.

Colin Bull, a research consultant with software testing company SQS, said deploying the pricey missile was “overkill and potentially ineffective.”

“If drones fall into the wrong hands, there’s currently nothing to stop someone flying a payload-laden drone into restricted airspace, without action such as this taking place,” he said.

“Rather than using expensive military resources to deal with potentially rogue drones, implementing regulation and the standardization of radio frequencies, on which drones operate, is vital to combat such threats,” he added. “Ultimately, this makes it easier for security teams to use jamming devices to stop a suspect drone from entering the space.”

Justin Bronk, a researcher at the Royal United Services Institute, agreed with Bull’s assessment.

“It certainly exposes in very stark terms the challenge which militaries face in attempting to deal with the adaptation of cheap and readily available civilian technology with extremely expensive, high-end hardware designed for state-on-state warfare,” he told the BBC.

He also said the high-tech Patriots might struggle to target the drones, which typically have top speeds of about 50 mph.