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 has stated that the situation remains difficult.

Meanwhile, army chief Oleksandr Syrskyi reports a deterioration on the front line in the southeastern Zaporizhzhia region, citing losses of three settlements.

Syrskyi emphasized, however, that Russian activity is most concentrated around Pokrovsk. A viral video depicts Russian soldiers utilizing civilian vehicles to navigate through fog-covered roads.

The BBC has verified the video's location as the southern outskirts of Pokrovsk, along the Selidove-Pokrovsk highway.

Due to low visibility over several days, drone operators encountered significant challenges in carrying out aerial reconnaissance missions. This lack of visibility has given Russian troops the confidence to move in columns that would typically be exposed to immediate drone attacks.

Despite some success in repelling small Russian groups on foot and motorbikes, Ukrainian drone pilot Goose noted that the video evidence of their counterattacks was compromised by weather conditions.

As the conflict intensifies, the presence of Russian forces in Pokrovsk is becoming increasingly evident. According to military mapping by the Ukraine-based DeepState monitoring group, significant areas of the city are now under Russian control.

Ukrainian troops are striving to prevent a complete encirclement of Pokrovsk, as Russian forces aim to cut off supply routes through targeted assaults supported by both drones and ground troops. Tactical infiltration has proven effective for the Russians, often leading to chaos within Ukrainian defensive lines and subsequent advances.

As the battle for Pokrovsk rages on, the situation remains precarious for Ukrainian defenders, necessitating sustained vigilance against an enemy emboldened by weather conditions.