Ukraine's defense of Lysychansk -- the last city in the Luhansk region it still holds -- just became a lot more tenuous.

For weeks, Russian forces have been trying to obliterate Ukrainian defensive positions to the south and east of the city, in an effort to encircle and cut off Ukrainian troops tasked with holding it.

A Ukrainian serviceman looks on after a strike on a warehouse near Lysychansk on June 17, 2022.

In the last couple of days, the Russians have advanced into several villages south of Lysychansk, though not without sustaining losses from Ukrainian artillery fire. Indeed, the Ukrainian military claims that some Russian battalion tactical groups are being consolidated or withdrawn to restore their combat capabilities.

The Institute for the Study of War, in its latest daily analysis of the battlefield, says the Russian breakthrough from the south means they "may be able to threaten Lysychansk in the coming days while avoiding a difficult opposed crossing of the Siverskyi Donets River."

The settlements that Ukrainian officials confirmed as lost Wednesday are all on the western Siverskyi Donets Riverbank, within 10 kilometers of the southern outskirts of the city."The Russians are approaching Lysychansk, entrenching in nearby towns. The city is being shelled by aircraft," according to Serhiy Hayday, head of the Luhansk regional military administration.