(CNN) Russian forces in the occupied Kherson region in southern Ukraine are finding it increasingly difficult to maintain the flow of ammunition, armor and fuel to front-line units, according to Ukrainian officials and Western analysts, thanks to a concerted Ukrainian campaign to cut off river and rail supply lines as well as target ammunition depots.
Ukrainian officials say the Russians are moving command posts from the north of the Dnipro River to the south bank as bridges have been heavily damaged.
The first deputy head of Kherson regional council, Yuri Sobolevsky, claimed on his Telegram channel that a significant portion of the Russian military command had already left Kherson city. Ukrainian forces are about 25 kilometers (15.5 miles) north of the city, towards Mykolaiv.
Much of Kherson region has been occupied since the beginning of Russia's invasion of Ukraine. As part of Kyiv's counteroffensive to try to retake lost territory in the south, Ukrainian forces are targeting critical bridges to disrupt supply routes in and around Kherson.
The Institute for the Study of War, a US-based think tank, said Sunday that the Russians may be leaving for the other side of the river "to avoid being trapped in Kherson city if Ukrainian strikes cut off all ground lines of communication connecting the right bank of the Dnipro River to the Russian rear."
Videos have appeared on social media in the past few days showing renewed long-range artillery attacks on the Antonivskyi bridge and a road bridge over the dam near Nova Kakhovka, rendering them impassable for heavily armored vehicles. In some areas, the river is up to 1 kilometer (0.6 miles) wide, making pontoon bridges impractical.
The Ukrainians have also targeted several railway lines from the Russian-occupied Crimea Peninsula into the Kherson and Zaporizhzhia regions. On Tuesday, a series of fierce explosions rocked the town of Dzankhoy on the main line towards Kherson. Recent video showed a substantial stock of military vehicles and ammunition at the site.
Ivan Fedorov, the mayor of occupied Melitopol, said on Ukrainian television Monday that Russian forces were still clearing rubble from the site of a railway bridge near the city that had been hit last Friday.
"Currently, the enemy uses Melitopol as a logistics center for the transportation, trans-shipment of ammunition and heavy weapons. The enemy transports most of the ammunition by rail," he added.
Fedorov, who is no longer in Melitopol, also claimed Monday: "We see the migration of [Russian] military personnel from Kherson to Melitopol. Military personnel take their families out of Melitopol."
Fedorov says he gets information from partisan networks in the city.
Two railway lines from Crimea were struck in the last 10 days. Last week, local residents reported several hours of explosions in the Henichesk district, a port area along the Sea of Azov, and the railway further west at Brylivka was also struck.
According to the Ukrainian military's Operational Command South: "Within the last week we have destroyed over 10 ammunition warehouses and military equipment clusters. These hits do not allow for the heavy equipment to be transferred by these bridges."
None of this suggests an imminent Russian withdrawal from Kherson.
Russia has established strong, layered defenses, including air cover, in the Kherson region, according to Western military analysts, even using vintage T-62 Soviet battle tanks as stationary artillery pieces to provide defensive support.
They have also attempted regular counter-attacks against Ukrainian units trying to push south into Kherson, essentially restricting them to modest gains in the flat farmlands along the border with Mykolaiv region.
But the Russians require a constant flow of munitions and fuel to sustain their operations in the region. And bridges and railroads are easy targets.
Now that the United States has supplied them with anti-radar HARMS missiles, the Ukrainians have begun using combat aircraft and helicopters in the region, as well as highly accurate long-range artillery systems. Their targeting is also aided by a nascent resistance movement within occupied areas.
The Ukrainians have recognized that going toe-to-toe with Russian forces in a gruelling battle of artillery and tanks is far less fruitful than using their newly acquired tools -- and some older ones -- to hit Russian rear positions and infrastructure.