Foam decoys, 'vacuum' warheads, and improved navigation are making Russia's drone attacks larger and more difficult to defend against, experts say.
Moscow is unleashing its expanding arsenal of Unmanned Aerial Vehicles (UAVs) on Ukraine at a rate and intensity never seen before.
A record number of drones were launched across 17 regions in a single attack this week, striking apartment blocks and critical infrastructure.
A second major attack followed, targeting energy facilities and cutting power to more than 1 million people.
Analysts say Russia is now capable of producing up to 100 attack drones a week, and is fitting them with more destructive warheads.
And with a number of countries reportedly helping Moscow circumvent sanctions, it is becoming more difficult for Ukraine to keep up.
From a few to hundreds
Security expert Maria Avdeeva, a non-resident senior fellow at the Foreign Policy Research Institute, said Ukraine had witnessed Russia's drone capabilities growing.
"We have seen how it has developed from just a few drones overnight to over 100 at a time," she told the ABC.
About 188 drones were launched at Ukrainian cities on Tuesday, local authorities said.
It was the largest single drone attack since the start of the full-scale war.
"The enemy launched a record number of Shahed attack UAVs and unidentified drones," Ukraine's air force said, adding that four Iskander-M ballistic missiles were also used.
"Unfortunately, critical infrastructure facilities were hit, private and apartment buildings were damaged in several regions due to massive drone attacks."
Ukraine said its air defences shot down 76, while it lost track of 96.
Another major strike was carried out two days later, with Russia firing 91 missiles and 97 drones in an attack on energy infrastructure, Ukraine's air force said.
It triggered deep power cuts across the country, as temperatures dropped below zero degrees.
US President Joe Biden condemned the attack, calling it "outrageous".
Russian President Vladimir Putin said the strikes were in response to Ukraine's strikes on Russian territory with US medium-range ATACMS missiles.
The evolution of Shahed drones
Russia has been hammering civilian areas of Ukraine with increasingly heavy drone attacks since the middle of the year.
British intelligence said the increased use of attack drones since mid-2024 had changed the nature of the conflict, adding that Moscow was "continually targeting" critical infrastructure.
Russia has consistently denied that it intentionally attacks civilian targets in Ukraine.
Russia's weapon of choice for these strikes throughout most of the conflict has been Iranian-made Shahed 136 attack drones.
The cheaply-produced "suicide" drones were mostly imported, but Russia has tweaked the model and now mass produces them locally.
Ms Avdeeva said there were several production plants dedicated to making the drones, churning out up to 100 a week.
"This means that they can constantly increase the production and constantly increase the number of attacks on Ukraine," she said.
Ukrainian President Volodymyr Zelenskyy said Russia had been deploying 10 times more Shahed drones than at this time last year.
Russia has made engine adjustments and simplified other elements of the original Iranian design to reduce costs and expedite production cycles.
According to analysis by the US-based Institute for Science and International Security, satellite imagery showed that the number of facilities producing components for Shaheds in Russia had increased.
The report stated that a plant in Tatarstan's Alabuga zone had reached its goal to produce 6,000 drones by September 2025 a year ahead of schedule.
Shaheds are kamikaze drones, which means that they are not designed to return to base after an attack.
They are loaded with built-in ammunition and dive towards a target to explode on impact.
They have the ability to evade radar detection and can operate at a range of almost 2,500 kilometres.
The drones used to only fly on a pre-programmed route, but Ms Avdeeva said advancements had enabled them to be pilot-operated and keep contact with navigation bases.
"They are now much more dangerous and harder to shoot down," she said.
According to Ukrainian officials and analysts, the drones are also being equipped with thermobaric warheads.
Thermobaric warheads create a fire cloud that can reach between 2,400 and 2,600 degrees Celsius.
Also referred to as vacuum bombs, the warheads create a vortex of high pressure and heat that penetrates the thickest walls.
They are also loaded with ball bearings to cause maximum damage even beyond the superheated blast.
Oleksandra Molloy, the aviation program lead at UNSW, recently completed an in-depth investigation into the evolution of drone warfare for the Australian Army Research Centre.
She said Russia was continuously customising Shaheds and changing the warheads.
But the thermobaric warheads were being increasingly used because it could cause more damage.
"It is usually aimed at buildings because it can have that, unfortunately, more destructive effect," she told the ABC.
Arthur van Coller, an expert in international humanitarian law at South Africa's University of Fort Hare, said thermobaric weapons could have extreme physical effects.
Even if people are caught outside the initial blast site, they can cause collapsed lungs, crushed eyeballs, and brain damage.
Russia's foam decoy drones
Huge swarms of cheap foam decoy drones were also being used alongside Shaheds in mass attacks.
Powerful missiles often follow close behind as air defences are exhausted by the drones.
One of the main models being spotted in the battlefield is Russia's long-range Gerbera drone, which is made from cheap materials such as polystyrene foam and plywood.
It is similar in shape but slightly smaller than the Shahed-136, and almost indistinguishable on radars.
Dr Molloy said it was difficult to detect whether drones were carrying a warhead until they reached a target, so air defences were forced to try and take them out.
"They fly as a deception, and can be very, very cheap, like 100 or 200 dollars," she said.
Decoy drones are generally unarmed, but a recent report by the Defense Intelligence of Ukraine (DIU) found that the Gerbera had additional strike capabilities.
In addition to using live feed cameras to detect Ukraine's air defence positions, they could be fitted with warheads and used as "kamikaze" attack drones, the report said.
And they were approximately 10 times cheaper than the Shahed, which has been estimated to cost anywhere between $US20,000 ($30,700) to $US50,000.
Defence 'more and more difficult'
While the Gerberas were being developed at a factory in Russia, the DIU found that they feature a Chinese engine and other foreign components.
Mr Zelenskyy has attributed Russia's increased drone capabilities on Moscow's ability to circumvent sanctions through various schemes.
"We need more joint effort so that the sanctions work and force Russia to stop this war," he wrote on the Telegram messaging app.
Dr Molloy said it was clear Russia's goal was to keep scaling up drone production, and stronger sanctions were needed.
But whether they would work or not was another story.
"We have witnessed a so-called black market, or Russia just being able to go around the sanctions," she said.
Ukraine was working on different drone interceptors and systems to target Shaheds, but going into winter they would be needing more support to protect the skies, she added.
The US said it had been prioritising air defence exports to Ukraine since earlier this year and further deliveries were underway.
Ms Avdeeva said there were several layers of defence to repel the drone attacks, but with volumes increasing it was becoming "more and more than difficult".
"In this war of drones, in this war of technologies, it is a constant challenge for who will develop the better capabilities to either defend or attack," she said.
ABC/Wires
