Russian engineers are producing hundreds of interceptor drones designed to overwhelm Ukrainian defenses as cover for a terrifying new weapon, an investigation has found.

A factory in Russia’s Alabuga Special Economic Zone recently began producing thermobaric drones alongside decoys, Associated Press reporters revealed.

Thermobaric foci create a vortex of high pressure and heat that can penetrate thick walls.

They suck up all the oxygen in their path and have a fearsome reputation for the injuries they can cause even outside the original blast site, such as collapsed lungs, crushed eyeballs and brain damage.

Russia came up with the decoy plan in late 2022 and code-named it Operation Fake Target, according to a source.

Ukrainian forces must make split-second decisions about how to spend limited resources to save lives and preserve critical infrastructure.

“The idea was to make a drone that creates a sense of complete uncertainty for the enemy. So he doesn’t know if it’s really a deadly weapon … or essentially a foam toy,” the insider said.

With thermobaric, there is now a “huge risk” of an armed drone veering off course and ending up in a residential area, where “the damage will be just terrifying,” he said.

In recent weeks, decoys have filled Ukraine’s skies by the dozens, each appearing as an indistinguishable blip on military radar screens. On the first weekend of November, the Kiev region spent 20 hours on air alert, the sound of drones buzzing with the boom of anti-aircraft defenses and gunfire.

Unarmed decoys now account for more than half of the drones targeting Ukraine, according to Serhii Beskrestnov, a Ukrainian electronics expert whose black military van is equipped with electronic jammers to shoot down the drones.

It expanded after the 2022 invasion of Ukraine, and some sectors switched to military production, adding new buildings and renovating existing sites, satellite images show.

In social media videos, the factory promotes itself as an innovation center.

But David Albright of the Institute for Science and Homeland Security in Washington said Alabuga’s current purpose is only to produce and sell drones to Russia’s Defense Ministry.

The videos and other promotional media were removed after an AP investigation found that many of the African women recruited to fill labor shortages there complained they were tricked into taking jobs at the factory.

Russia and Iran signed a $1.7bn (£1.3bn) deal for the Shahed in 2022 after President Vladimir Putin invaded Ukraine and Moscow began using Iranian imports of unmanned aerial vehicles , or UAV, into combat later that year.

Shortly after the deal was signed, production began in Alabuga.

In October, Moscow struck with at least 1,889 drones — 80 percent more than in August, according to an AP analysis that has been tracking drones for months. Russia launched 145 drones across Ukraine on Saturday, just days after Donald Trump’s re-election called into question US support for the country.

Since the summer, most drones have been crashing, being shot down or being diverted by electronic jamming, according to an AP analysis of Ukrainian military briefings.

Fewer than 6 percent have reached a discernible target, according to data analyzed by the AP since late July. But the high numbers mean a handful can escape every day – and that’s enough to be deadly.