What had been a lightning push by Ukraine to drive Moscow forces out of eastern Kharkiv region slowed to a brutal mess on Saturday, stalled by heavy rain and Russian resistance.

In the front-line town of Kupyansk, against the backdrop of constant shelling, a column of dark smoke rose over the Oskil River, which separates the Ukrainian-held western bank from the eastern bank, which is still fought over by Russian forces.

“Right now the rain is making it difficult to deploy heavy weapons anywhere. We can only use paved roads,” Ukrainian army sergeant Roman Malyna told AFP as tanks and APCs maneuvered under the downpour.

“Because it is difficult to advance due to the weather, we are targeting their armored vehicles, ammunition depots and groups of soldiers for now,” he said.

On Friday, Kupyansk military administrator Andriy Kanashevych told AFP that it could take Ukrainian forces 10 days to fully secure the area.

Most of Saturday’s shelling was outward — Ukrainian artillery aimed at Russian positions in the woods beyond east of the city — but tension reigned with a Russian drone spotted overhead.

A trickle of refugees headed toward Ukrainian territory across the damaged bridge, whose railings were still painted the red, white and blue colors of the former Russian occupiers of Kupiansk.

Two Ukrainian soldiers, well equipped with US-style assault rifles and body armor and in good spirits despite fatigue and concern over the Russian drone buzzing over the debris-strewn street, also returned.

One of them, using the pseudonym “Mario,” said it was too early to say when the east bank would come under full Ukrainian control, but was confident the Russians were retreating.

“Only their bodies are left behind,” he boasted.

“In general everything is good considering the scale of the operation, we had almost no casualties,” he told AFP.

Most of Kupyansk, a key railroad hub once used by Russia to resupply its forces farther south on the Donetsk battlefront, fell to Ukraine in this month’s stunning counterattack against the invader.

But a narrow strip of the Kharkiv region on the east side of the Oskil River remains in Russian hands, preventing Ukraine from encroaching on the Lugansk region, which Moscow is holding and trying to annex.

“Yes, we have enough guns and men, but it depends on what happens on the other side,” Sergeant Malyna said, referring to Russian forces.

“They are trying to find the weak points in our line of defense. So they try to attack us with tanks and marines from time to time.

“Our morale is good. We are ready to fight, but we need more heavy weapons and more precision weapons,” he said, echoing a joint Ukrainian appeal for more advanced weapons from Kiev’s western allies.

As fighting rages on, many civilians have already fled a city that lacks electricity and running water and is grenades whistling.

However, some have nowhere to go and rely on food supplies.

Civilians still crowd around portable generators in the doors of five-story concrete apartment blocks as the rain pours down, charging tablets, flashlights and razors.

Most say they are glad Ukrainian troops have returned to liberate the city from Russian occupation, but the ongoing fighting has taken its toll.

Retired trapeze artist Lyudmila Belukha, 74, once performed for the Soviet-era Moscow Circus.

“I traveled all over the Soviet Union and also abroad,” she recalls.

The widow – her deceased husband was a circus artist – lives alone in a housing estate in Kupyansk.

Her sister has moved to Greece while she has had no news from her nephew, who lives on the east bank of the river, for months.

“I’m home alone with my cats. Absolutely alone. My kitchen and balcony windows are broken. I need plastic wrap to fix them because it’s getting cold. I’m freezing,” she said.

She picked up a food parcel from humanitarian volunteers and said she wasn’t hungry, but: “We have no water, no gas and no electricity. Nothing. There isn’t even an option to boil water for tea.”