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War for the south: Ukraine sets its sights on regaining cities and towns lost to Russian troops

Mykolaiv, Ukraine(CNN) A Ukrainian reconnaissance team squats in a modest home in a village near Mykolaiv. Machine guns and army knapsacks line the walls, sleeping bags lie rolled out on the floor, and a pot of soup warms on the stove.

Outside, the garden shed is stacked with Javelins and other shoulder-launched anti-tank weapons.

The soldiers smoking on the porch hardly notice the boom of incoming artillery shells landing some 10 kilometers away. Today is not their turn to fight on Ukraine's southern front.

The owners of the house, who fled to Poland after the war broke out in late February, are happy in the knowledge that their village is now back in Ukrainian hands.

Senior Lieutenant Andrii Pidlisnyi was one of the soldiers that drove the Russians out two months ago. "At first, it was a defensive operation to stop them," he says. "After that we found some good places where we can make offensive operations and take back our territories. And now we're doing that."

Ukrainian servicemen ride through Mykolaiv region in mid-June.

Pidlisnyi commands a unit of 100 men tasked with identifying Russian positions, often by drone. They then call in the artillery.

On his computer, he shows CNN bodycam videos from his missions earlier in the war. He has had some close calls, but says his morale is high after recent successes. US hardware has helped.

One video shows Pidlisnyi sitting in a trench, using his drone to pinpoint Russian tank positions. "Call in the American gift," he says over the radio.

Russian troops are now on the defensive in this part of the south -- unlike in the east, where Ukrainian troops are the ones being forced to cede ground.

But here too, it is a slog. The aim for soldiers like Pidlisnyi is to take small strategic pockets, areas of high ground with views of occupied Ukrainian towns in the distance, from where further gains can be made.

"I'm not sure we will win it [by] the end of this year," he says, referring to retaking Russian-occupied areas in Ukraine's south. "Maybe not until the end of next year."

The Ukrainian troops claim to have won back some territory. They say they pushed the Russians out of two more villages along the Mykolaiv-Kherson border early this week.

But it is a large area of open rolling farmland where any advancing forces would be exposed, and the Russians have had several months to build defensive positions in three layers across the region.

And the Ukrainians have limited assault forces -- for much of this conflict they have been playing defense and that has degraded some of their best units.

Weapons provided by Western allies are, by and large, not designed for ground offensives, and the Ukrainians are short of air cover for any advancing forces.

Ukrainian forces have also been sustaining heavy losses in the south, though the military rarely provides details.

There are growing signs that the Russians are reinforcing their military presence in Kherson, determined to hold it as a vital part of the land bridge to Crimea -- and as the peninsula's main source of water.

In the past two weeks large convoys have trundled west from Mariupol through Melitopol to Kherson.

An armoured truck emblazoned with a pro-Russian "Z" symbol parked near Ukraine's former regional council building in Kherson on July 25.

Many civilians have already fled. Ukrainian officials estimate that nearly half the population of Kherson has left the region for Ukrainian-held territory.

They accuse the Russians of preventing more people from leaving cities like Melitopol, in the occupied Zaporizhzhia region, so that they can be exploited as "human shields" in the event of a Ukrainian offensive.

Shifts on the battleground

Ukraine's southern front begins near Mykolaiv, a port city to the north of Russian-held Kherson city. It is struck by missiles and rockets almost every day.

To the south and east, a meandering front line runs from the Black Sea coast through farmland and up towards Zaporizhzhia region.

This area is a long way from the calcified Donetsk front -- fought over since 2014 -- but it is now just one part of a battlefield that stretches for more than 1,000 kilometers.

Along the line, artillery pieces face off, in battles one Ukrainian soldier described as "ping-pong with cannons."

It has been that way for months.

Now, the Ukrainians say they have an advantage: Donated weaponry, particularly the HIMARs rocket system supplied by the US, is taking out crucial storage depots and command posts and ammunition dumps deep in Russian-held territory.

Firefighters work to extinguish a blaze after a Russian military strike in Mykolaiv on July 14.

This month, Ukraine says it destroyed at least two ammunition dumps at Nova Khakova in the Kherson region. Ukraine has also hit three bridges across the Dnipro River, and even a transport of Russian S-300 missiles -- a revamped surface-to-air projectile which has rained horror on Mykolaiv.

On Thursday, the UK Ministry of Defense said Russia's 49th Army, stationed on the west bank of the Dnipro River, "now looks highly vulnerable" after Ukrainian long-range artillery hit the three bridges.

"One of these, the 1,000-metre long Antonivskyi bridge near Kherson city, was damaged last week," and after a further strike this week "it is highly likely that the crossing is now unusable," the Defense Ministry said.

It contended that "Kherson city, the most politically significant population centre occupied by Russia, is now virtually cut off from the other occupied territories."

However the Russians still control large areas to the northeast of the city and may be able to resupply forces on the west bank with pontoon bridges and river ferries across the Dnipro. And more Russian hardware will replace what is lost.

CNN has obtained exclusive video footage, taken by partisans, showing S-300 missiles at Dzhankoi railway station in occupied Crimea. Satellite imaging and analysis provided by Maxar indicates as many as 50 S-300 missiles on railcars at the station on Thursday 21 July. Just one S-300 could destroy a building somewhere in Ukraine.

Yet despite the enormity of the Russian war machine, Ukraine's military leaders have said this month's strikes on Russian stores and resupply routes could turn the tide on the battlefield.

Now, multiple frontline soldiers have backed that up -- telling CNN they believe the Russians have noticeably fewer rounds to fire at them.

"We had about two to three weeks where they didn't have enough ammunition to fight us with artillery, rockets and so on," Snr Lt Pidlisnyi says.

On another part of the southern front, Ukraine Armed Forces Captain Volodymyr Omelyan tells CNN surgical strikes behind enemy lines are a part of an ongoing modernization Ukraine's strategy.

"We believe that Russians will surrender much faster, especially in Kherson region when we already hit three main bridges, two automobile bridges and one railway one," says Omelyan, who was a politician before he joined the army.

Omelyan says gains are being made "day by day" on the battlefield, but that Ukraine chooses not to advertise them: "It's a good policy of our commanders to talk about what's happening after it's already happened."

Readying for a long fight

In the southern industrial town of Kryvyi Rih, Ukrainian forces are put through their paces: Reservists and national guardsmen armed with pellet guns must storm a house. Ukrainian police are on the level above, playing the part of the Russians.

Smoke rises over the city skyline in Kryvyi Rih in late June.

After an hour of mock fighting, the trainees have failed to take the top floor -- a sign of how deadly and difficult hand-to-hand urban warfare is.

Their commander, Oleksander Piskun, was gravely injured pushing Russian-backed separatists out of cities in the eastern Donbas region in 2014, and has used a wheelchair since.

"Street combat, the battle to storm a settlement is the hardest combat," he says. "It is more difficult because we are not capturing settlements, we are liberating settlements. These are our cities, these are our people."

For now, the fight on the southern front is dominated by artillery, not by street combat. Ukrainians say the future will bring an assault on Kherson, but first, the long-range battle must be waged and won.

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