Thick fog has enabled Russian troops to move further into the key strategic city of Pokrovsk in eastern Ukraine.
Ukraine's 7th Airborne Assault Corps says weather conditions, particularly dense fog, have prompted Moscow to intensify its bid to get increasing numbers into the ruined city and encircle Ukrainian forces.
Russian forces have spent more than a year trying to seize the city. Ukraine's military says there may now be 300-500 Russians there and President Volodymyr Zelensky says the situation remains difficult.
Meanwhile, army chief Oleksandr Syrskyi says the situation on the front line in the southeastern Zaporizhzhia region has significantly worsened, with the loss of three settlements.
Syrskyi stated that Russia is most active around Pokrovsk. A video has gone viral on social media showing Russian soldiers openly driving through a hazy road on civilian cars and motorbikes.
The BBC has verified the location where the video was filmed as the southern outskirts of the town on the Selidove-Pokrovsk highway.
For several days fog obscured visibility to carry out aerial reconnaissance, says a drone pilot from the Shershni Dovbusha unit of the 68th brigade with the call-sign Goose.
That's why, he told the BBC, the Russians had even dared to launch assaults using a column of vehicles, which would normally have been wiped out immediately by Ukrainian drones.
A week ago, Zelensky estimated that up to 300 Russian soldiers were fighting in Pokrovsk. The video suggests those numbers have likely increased in that time, with military confirmations indicating southern areas of the city are now under Russian occupation.
Russian troops appear to be closing in on most areas of Pokrovsk, according to mapping by the Ukraine-based DeepState monitoring group. Some observers say that its fall is imminent.
Most parts of the city are now in a grey zone that neither side fully controls, says Goose. We might hold positions in one building, but the enemy can be in the next one. They're trying to get behind our backs, he says.
Moscow is attempting to encircle Pokrovsk and neighboring Myrnohrad in what is known as a cauldron. Even if the lid is not closed, Russians can constantly target all routes in and out of it using FPV drones.
To prevent such an encirclement, Ukrainian troops have pushed Russian troops back from Suvorove and Rodynske on the eastern part of the cauldron, creating a bigger gap between Russian flanks.
This infiltration tactic has proved quite successful, pinpointing that Russian forces are specifically targeting Ukrainian FPV pilots to limit the resources available for detecting smaller Russian groups.
As the Kremlin attempts to reinforce in other front line areas, the situation remains dire with ongoing conflicts across various Ukrainian territories.
