Russia has gained five-miles of territory in a sudden advance exploiting a blunder in the rotation of Ukrainian forces.

Moscow was able to capture the village of Ocheretyne, northwest of Avdiivka, in a thrust following the withdrawal of Kyiv’s battle-hardened 47th Brigade.

The brigade – which was formed to spearhead Ukraine’s failed summer counter-offensive last year and is equipped with American-made armoured vehicles and trained by Nato – has been fighting without a break for almost 12 months.

After the culmination of Kyiv’s southern offensive, it was redeployed to reinforce Avdiivka, the Donetsk region city, which fell under Moscow’s control in February.

Over the weekend, Ukraine’s 115th Brigade was ordered to replace the 47th where they were defending the front line just east of Ocheretyne.

But as the 47th were pulling back, Russian forces launched an attack that put them within striking distance of the newly fortified defensive lines between the frontline and a 20-mile-wide area of undefended land leading to the city of Pokrovsk, a key logistical hub for Kyiv’s defence of the Donbas.

Mykola Melnyk, a company commander in the 47th who lost a leg during the summer offensive, wrote on social media: “The drastic advancement of the Russians became possible because certain units just f---ed off positions.

“Hope they get trained and retrained into storm troopers.”

The gap created by the absent 115th allowed Russia’s 30th Motor Rifle Brigade to push along a railway line running north west out of Avdiivka into Ocheretyne.

The latest update by authoritative Ukrainian Deep State website, which maps changes on the battlefield, on Wednesday showed the majority of the village under the control of Russian forces.

Moscow’s defence ministry claimed Ukrainian troops had fled Ocheretyne in small groups under heavy Russian fire.

Footage shared online by pro-Kremlin military bloggers appeared to show the Russian flag flying above the battle-scarred village.

Lieutenant Melnyk wrote that the only reason Russian forces weren’t able to advance deeper into Ukrainian-held territory was because the 47th rejoined the fight.

“The holes that turned out to be clogged by those who were planning to take recovery,” he said on social media. “The 47th brigade is back in business. Another month and there will be a year without rotation.”

Moscow has brought in reinforcements from other parts of the frontline to support its troops advancing through Ocheretyne.

Russian forces are within less than 20 miles of the garrison town of Pokrovsk. The city, which is used to rotate soldiers and equipment because of its transport links to Kyiv, has been within Russian long-range fire since the fall of Avdiivka.

Ukrainian forces lost a Himars rocket launcher and a Patriot air-defence launcher being moved through the city – the first recorded losses of the prized American-made systems.

Kyiv’s troops fighting in Donetsk are under mounting pressure ahead of the expected arrival of fresh US military aid, with Joe Biden set to sign off on a $60 billion package.

Further north of Ocheretyne, Russia has amassed some 25,000 troops in a bid to capture the town of Chasiv Yar.

The strategic settlement is on high ground that would give Russia a foothold to launch offensives against the garrison cities of Kostyantynivka, Druzhkivka, Kramatorsk and Slovyansk.

It would also give Moscow’s forces defensible positions to unleash long-range attacks on road and rail links connecting Ukraine’s forces in Donetsk to Kyiv.