In a coordinated counter-attack, a Ukrainian river boat squad – possibly a special forces team – had been able to identify when the Russians began building the pontoon. Visibility was virtually nil, because Russian troops had thrown smoke grenades and set nearby trees on fire.
Ukrainians had waited until they heard the chugging of Russian tugs building the bridge, monitored its progress and then called in artillery and drone strikes. The footage, taken by drone, shows the carnage in the wake of the Ukrainian assault: at least two and possibly three temporary bridges sunk, and the remains of Russian military vehicles scattered on both sides of the river bank and in the woods beyond. Russian troops had succeeded in crossing the river and had then been left stranded and open to massacre.
Ben Barry, a retired brigadier and former director of British Army staff at the Ministry of Defence, said: "No one pretends river crossings are easy but the higher the standard of military leadership, command and tactical training the more likely it is to be achieved."
Barry, the senior fellow for land warfare at the International Institute for Strategic Studies, had seen the photographs of the battlefield, adding: "These reports are consistent with other evidence of Russian military performance from fighting in Kyiv and Kharkiv. Doing a river crossing is one of the most difficult things to do in warfare." In other words, a well-trained army would struggle to cross the Siverskyi Donets river and the Kremlin's forces are not in that category.
The Siverskyi Donets (Donets for short) flows for 1046km through the Donbas, the region in eastern Ukraine to which fighting has switched after Vladimir Putin gave up on his plan to claim a swift victory by grabbing Kyiv and unseating President Volodymyr Zelensky. The Donets starts in Russia and winds its way southeast through Ukraine before re-entering Russian territory, and flowing into the Don that empties into the Sea of Azov at Rostov-on-Don.
The Kremlin forces had hoped to cross the Donets near Bilohorivka, an impoverished town in the Luhansk region. A Russian battalion, it is thought, had tried to cross in order to surround Lysychansk, an industrial hub in the Donbas 2.5km away.
Maxim, in his post on Twitter, claims to have identified the location of the planned crossing on May 7 and reported it back to his unit. A day later, the sound of Russian tugboats manoeuvring into position was detected, signalling the start of the assault.
There will inevitably be speculation that Ukraine had further help from the West. The Washington Post reported on Thursday that "information about the location and movements of Russian forces is flowing to Ukraine in real-time" and that that information "includes satellite imagery and reporting gleaned from sensitive US sources", likely to mean high-tech espionage surveillance on Russian command posts.
"The intelligence is very good. It tells us where the Russians are so that we can hit them," one Ukrainian official told the Washington Post. The official then made a hand signal to imitate a bomb falling on its target.
Russia's progress in the Donbas has, like its previous assault on Kyiv, stalled badly. Its inability to cross rivers will play its own part.
Maxim wrote on Twitter under the heading: "What I did to destroy Russian pontoon bridge", explaining that on May 6 he had been dispatched to the river for engineering reconnaissance after intelligence reports emerged of Russian troops gathering on the other side.
"I explored the area and suggested a location where Russians might attempt to mount a pontoon bridge to get to the other side", wrote Maxim, using rangefinders to estimate the river's width at 80 metres, requiring eight platforms each 10 metres long to span it.
"With that flow of the river, I knew they would need motorised boats to arrange such a bridge, and it would take them at least two hours of work," he said, relaying the information to his commanders, adding: "Also, I told the unit who observed that part of the river that they need to be on the lookout for the sound of motor boats. Visibility was s— in the area because Russians set fields and forests on fire, and were throwing a lot of smoke grenades. On top of that, it was foggy."
"They had to hear the sound. And they did on May 8th early morning. Right at the place I said. I was there to check it as well – and I have seen with my drone as Russians do the pontoon bridge. Reported immediately to commanders".
He had, boasted Maxim, "outplayed" Russia's military engineers because its engineers had "attempted to place a bridge RIGHT in the place where I guessed".
Russian forces had succeeded in putting in place the pontoon and troops and vehicles had begun moving across it. At that point, said Maxim, "the combat started".
Twenty minutes after the reconnaissance team had confirmed the Russian bridge's existence, heavy artillery began shelling its location. The Ukrainian army's 17th tank brigade, operating T-64 tanks and BMP armoured vehicles, opened fire deploying its 2S1 122-millimetre tracked howitzers, according to reports.
The shelling destroyed T-72 and T-80 Russian tanks, and two dozen armoured tracked vehicles as well as bridging equipment and a tugboat. "I was still in the area and I have never seen/heard such heavy combat in my life," said Maxim.
With Russian troops stranded on the wrong side of the river, engineers tried to build a second pontoon to rescue them. That too was blown up, with drone footage showing two platforms wedged on the river bank on the Russian side, but going nowhere.
"Their strategic objective was to cross the river and then encircle Lysychansk. They miserably failed," said Maxim, citing reports of as many as 1500 dead soldiers. The death toll is likely to have been lower but the casualties still large for an exposed Russian battalion subject to heavy bombing.
Bridges can take on a deeper significance in warfare. Think Bridge on the River Kwai (and the brutal treatment of British PoWs building the Burma railway) or else a Bridge Too Far that depicted in cinema the battle to control the bridges at Arnhem. The bridge over the Donets may yet go down in history as the best evidence yet of the Kremlin's military failures in Ukraine.
