Russian forces are intensifying efforts to seize the eastern Ukrainian city of Avdiivka as Moscow's war in Ukraine grinds on.
The fighting is reminiscent of the battle for another eastern city, Bakhmut, which fell to Russia last May after months of grinding urban combat, 15 months into a full-scale invasion that Moscow calls a "special military operation".
WHAT IS AVDIIVKA?
Avdiivka, which had a pre-war population of around 32,000 and is called Avdeyevka by Russians, has been a frontline city since 2014, when it was briefly occupied by Moscow-backed separatists who seized a swathe of eastern Ukraine.
Today, authorities say fewer than 1,000 residents remain, many sheltering in cellars and basements. Officials say not a single building remains intact.
Avdiivka sits in the industrial Donbas region, 15 km (nine miles) north of the Russian-controlled city of Donetsk. Before the war, its Soviet-era coke plant was one of Europe's top producers.
Russian-backed officials describe the city as a "fortress" with concrete bunkers. They say defenders are holed up in tower blocks that cannot be stormed head-on without huge losses, and are using the coking plant as a base and weapons depot.
FIERCE FIGHTING
Ukrainian and Western analysts say Russia's offensive on Avdiivka is taking a huge human toll.
Last November, British military intelligence said the fighting had contributed to "some of the highest Russian casualty rates of the war so far".
"Every day there are new fresh forces, regardless of the weather, regardless of anything - of losses," one member of Ukraine's 47th Separate Mechanized Brigade told Radio Liberty.
"But no matter what, they keep crawling - literally over the bodies of their own."
Russian war bloggers, whom the Kremlin has brought under tight control, have acknowledged heavy Russian losses but alleged significant Ukrainian losses too.
They say Kyiv's forces can be encircled if Russian forces can cut their last main supply line to the west.
President Vladimir Putin on Jan. 31 stressed Avdiivka's significance and said a group of military veterans had recently advanced ahead of the army to seize 19 buildings - a claim that, like other battlefield reports, Reuters cannot verify.
Russia has been carrying out air strikes with targeting assistance from special forces, and using artillery, drones, helicopters and tanks as well as infantry, according to spare but regular Russian defence ministry updates.
WHAT'S AT STAKE?
Both sides see the city as key to Russia's aim of securing full control of the two eastern "Donbas" provinces - Donetsk and Luhansk. These are among the four Ukrainian regions Russia says it has annexed but does not have full control of.
Avdiivka is seen as a gateway to Donetsk city, whose residential areas Russian officials say have been shelled by Ukrainian forces, sometimes from Avdiivka.
Seizing it could boost Russian morale and demoralise Ukrainian forces, which have made only incremental gains in a broad counteroffensive since June. Ukrainian President Volodymyr Zelenskiy himself visited in December.
"If the Russian army takes control of the (supply) road, the Ukrainian armed forces will evidently be forced to withdraw from Avdeyevka. That will be a great victory for the Russian army," Sergei Markov, a former Kremlin adviser, said on Feb. 5.
Mykola Bielieskov of the National Institute for Strategic Studies, an official think-tank in Kyiv, said taking Avdiivka would not decisively tip the situation in Moscow's favour but "would make the situation more tenable for occupied Donetsk as a major Russian logistics hub".
Bielieskov believes the battle is driven by a Kremlin desire to strengthen the hand of Western sceptics calling for a cut in support for Kyiv, citing the limited impact of billions of dollars in military aid.
