After claiming to have conquered the adjacent rail hub of Lyman, Russian forces have stepped up their assault on the Ukrainian city of Sievierodonetsk, as Kyiv reinforced requests for longer-range weapons from the West.

Russian victories in eastern Ukraine’s Donbas, which includes the Luhansk and Donetsk regions, have been slow but steady in recent days, indicating a slight momentum shift in the war, which is now in its fourth month.

Invading forces looked to be on the verge of capturing the entire Luhansk region, one of the more modest war objectives established by the Kremlin after abandoning its attack on Kyiv in the face of Ukrainian resistance.

On Saturday, Russia’s defense ministry said its troops and allied rebel forces have complete control of Lyman, a railway junction west of the Siverskyi Donets River in the Donetsk region.

According to a private source, Ukraine’s deputy defence minister, Hanna Malyar, claimed the struggle for Lyman was still going on.

The Russians were attacking Sievierodonetsk, which is 60 kilometres (40 miles) east of Lyman on the other side of the river and the largest Donbas city still held by Ukraine.

“Sievierodonetsk is under enemy fire at all times,” Ukrainian police said on social media.

Russian artillery was also pounding the Lysychansk-Bakhmut road, which Russia must take to close a pincer movement and encircle Ukrainian forces.