By Andrew Osborn and Felix Light
(Reuters) - The nearly five-month battle for the small city of Bakhmut in eastern Ukraine has ground on for so long and wrought so much death and destruction that, even if Russia does prevail, it will be a pyrrhic victory, military experts say.
Wrecked apartment blocks, badly wounded soldiers, mud-filled trenches and civilians cowering in cellars under incessant bombardment have become familiar scenes in and around Bakhmut since the fighting began.
Gaining control of the city, with a pre-war population of 70-80,000 that has shrunk to close to 10,000, could give Russia a stepping stone to advance on two bigger cities - Kramatorsk and Sloviansk.
It would also deprive Ukraine of a useful road and rail supply line intersection.
But with fierce fighting there since Aug. 1, and Russian shelling since May, much of Bakhmut lies in ruins, while Ukrainian forces to the west have had ample time to build defensive lines nearby to fall back to.
"If Bakhmut had been captured when they started their attack in August then it would have been significant. But it's all about momentum," said Konrad Muzyka, a Polish military analyst.
He said Bakhmut's strategic value had been reduced by Ukraine's fortification of the surrounding area in the months that followed, making it hard for Russia to convert the city's capture, if it happens, into a broader breakthrough.
Still, the clash has taken on outsized significance on both sides because it is the main theatre of fighting as winter bites, major resources have been deployed and it is the first battle in months Russia appears to have a chance of winning.
Described as a "meat grinder" by commanders on both sides, some Russian, Ukrainian and Western experts liken the struggle to World War One, where Germany and Britain suffered huge losses in trench warfare for often scant territorial gain.
Igor Girkin, a Russian nationalist and former Federal Security Service officer who helped launch the original Donbas war in 2014 and is under U.S. sanctions, said this week he thought his own side's strategy in Bakhmut was "idiotic".
"What will happen next (after the potential Russian capture of Bakhmut)?" Girkin mused in a video, adding the Ukrainians would merely fall back to a second defensive line while continuing to build other defensive lines behind that one.
"It's chewing through the enemy's defences according to the World War One model," said Girkin, arguing that Moscow needed to change battlefield strategy and deploy its forces differently.
Michael Kofman, an expert on the Russian military at the U.S.-based CNA think-tank, said Moscow appeared committed to the battle because of resources it had already spent rather than because of "sound strategy".
"The fighting for Bakhmut is not senseless, but strategically unsound (for Russia) given weak offensive potential and no prospect of breakthrough even if the city is captured," said Kofman.
Neither side discloses the full extent of fatalities in Ukraine.
But Kyiv says Russia has been taking heavy losses and that many of those killed were convicts recruited by Moscow's Wagner private mercenary company.
Yevgeny Prigozhin, Wagner's founder, who is sanctioned in the West, has confirmed his men are fighting there.
The deal he offered convicts was to fight and be pardoned in six months or, if they joined up and deserted, face execution.
In November, independent Russian news outlet Mediazona reported that publicly available data from Russia's Federal Penitentiary Service showed the overall prison population shrank by over 23,000 people in September and October, the biggest drop of its kind in more than a decade.
That suggested convicts had taken up Prigozhin's offer. Reuters could not independently verify the data.
Prigozhin has cautioned against expecting rapid breakthroughs, and, in a Dec. 12 comment, said Wagner's task in fighting for Bakhmut was to "kill as many enemy soldiers as possible, and bleed the Ukrainian army dry".
Battlefield footage suggests intense fighting for relatively modest stretches of ground, with the frontline edging back and forth.
Russia, in its own battlefield updates, has spoken of Ukraine suffering heavy losses in men and hardware. Ukrainian President Volodymyr Zelenskiy said on Monday that Bakhmut was the "hottest spot" on a 1,300-km (800-mile )frontline.
WAR OF ATTRITION
For Russia, Bakhmut, which it calls Artyomovsk, the city's Soviet-era name, has long held political value.
Lying on the frontline that bisects Ukraine's eastern Donetsk region, taking Bakhmut would move Russia a step closer to full control of the Donbas, parts of which have been controlled by Russian proxies since 2014.
After Russian troops withdrew from Ukraine's north in April in a humiliating retreat, Moscow publicly reframed its core war aim as the "liberation" of the largely Russian-speaking Donbas, of which Donetsk region makes up roughly half.
Muzyka, the Polish military analyst, said Bakhmut had become a battle of attrition.
"The Ukrainians are just wearing the Russians down and it's quite effective in terms of manpower and equipment," he said. "They are increasing the costs to the Russians."
For Moscow, says British military intelligence, there is "a realistic possibility that Bakhmut's capture has become primarily a symbolic, political objective".
A win there would help lift morale and General Sergei Surovikin, overall commander of Russia's forces in Ukraine since Oct. 8, could show he was right to redeploy his forces elsewhere after withdrawing from the southern city of Kherson.
It could also boost Prigozhin's political capital in Moscow if he can take some credit for such a victory.
For Ukraine, say experts, the calculus in holding Bakhmut is partly about sustaining support from Western countries on whose arms supplies Ukraine's war effort is dependent.
With Ukraine having scored a string of battlefield successes, even a relatively insignificant defeat risks creating the perception of stalemate, which could make Western countries less willing to extend support for Kyiv amid their own mounting economic problems stemming from the war.
"At this stage, Ukraine is the victim of its own recent success, and suffers from heightened expectations of sustained momentum," said Kofman.
(Reporting by Andrew Osborn and Felix Light; Editing by Mike Collett-White and Nick Macfie)