- Russia and Ukraine have struggled to employ surprise in a war with so much drone surveillance.
- But Ukraine launched a shock incursion into Russia this week, appearing to catch it off guard.
Ukraine's new incursion into Russia shows that surprise is still possible despite ubiquitous surveillance, analysts said.
The Institute for the Study of War said in its update on Thursday that the "lack of a coherent Russian response" to Ukraine's advance into the southwestern Kursk region points to it catching Russia off guard.
That, and the significant progress Ukraine appears to have made in three days, "indicates that Ukrainian forces were able to achieve operational surprise along the border with Russia," the update said.
The element of surprise has been a rare thing during Russia's invasion of Ukraine, it noted.
Analysts have long observed that the proliferation of drones across the battlefield makes it hard for either side to move unseen.
"Both Russian and Ukrainian forces have struggled to achieve operational surprise in the past year and a half of fighting due to the partially transparent battlefield in Ukraine," the ISW said.
But partial transparency still leaves room for a sneak attack.
Ukrainian forces advanced into Kursk on Tuesday, with an audacity that contrasts with its prior strikes on targets inside Russia.
Those previous hits have relied on drones and missiles rather than ground forces.
The ISW said on Thursday that geolocated footage and accounts from inside Russia shows Ukraine was able to make "rapid advances."
It pointed to some Russian military bloggers — prominent sources of war updates in the absence of free Russian media — who said Ukrainian troops advanced up to 21 miles into Russian territory.
Little verified information about the advance is available, and Ukraine has not officially acknowledged it. But Ukrainian President Volodymyr Zelenskyy alluded to it in his nightly address on Thursday, saying "Russia brought the war to our land, and it should feel what it has done."
Russia seemed unprepared for such an attack, with officials offering conflicting information.
Drone dominance
Ukraine was able to catch Russia off guard despite being constantly watched.
The war in Ukraine has seen more extensive drone use than any prior conflict.
The extensive video surveillance of the battlefield has helped make the war a slow, grinding affair.
Being able to see the enemy preparing means neither side has made extensive use of surprise attacks that could make big gains.
Instead, fighting has been attritional, with each side trying to grind each other down with artillery strikes and ground advances.
Riley Bailey, a Russia analyst at the ISW, told Business Insider earlier this year that Ukraine's flat landscape and the proliferation of drones were stopping heavy weaponry like tanks being used to much effect.
"A lot of mechanized maneuver warfare on some level rests upon surprise on being able to rapidly advance and catch your enemy off guard," he said.
"By all indications, along the current front line, that's not really possible."
Expensive Russian surveillance drones are also allowing Russia to monitor and attack any build-up of Ukrainian troops and equipment.