Governor of Luhansk says Ukrainian troops retreating in some areas, as city of Lyman reportedly captured

• Ukraine-Russia war – latest updates

Officials in Ukraine have admitted that Russia has the “upper hand” in fighting in the country’s east, as Ukrainian forces fell back from some of their positions in the Donbas region.

Amid reports that Lyman, the site of an important railway junction, had largely been taken by Russian forces, Ukraine’s general staff reported that Russian forces were also advancing on Sievierodonetsk, Bakhmut and Avdiivka.

Bombardment continues in 40 towns including the key city of Sievierodonetsk as police in Lysychansk collect bodies for mass burials

• What we know so far on day 92 invasion

Fierce battles have continued to rage in eastern Ukraine with Russian troops on the verge of encircling a key industrial city, bringing a sharp rebuke of the west from Volodymyr Zelenskiy for not doing enough to help Kyiv win the war.

As the Ukrainian military reported on Thursday that 40 towns in the Donbas region were under Russian bombardment, Luhansk governor Sergiy Gaiday described fighting outside Sievierodonetsk, a key military goal for Russia, as “very difficult”, saying Russian troops were shelling the city from the outskirts with mortars.

Anton, released by Ukraine in a prisoner exchange, says he is only now registering the toll captivity took on mind and body

• Russia-Ukraine war: latest updates

Still getting used to the feel of his gun and military fatigues, Anton suddenly found himself surrounded by Ukrainian forces as bullets flew by, with one striking his arm.

“It was our first confrontation with the enemy; we hadn’t even fired a shot. They ambushed us, and we couldn’t fight back. We had to surrender,” said Anton, a 21-year-old Russian serviceman, in an interview with the Guardian.