Weary troops stuck on front line as Ukraine struggles to find manpower

Under the rich, leafy cover of the Ukrainian spring, an artillery unit awaits.

Only a fraction of their job is firing rockets from their 50-year-old launcher. Most of their time is spent digging a new bunker into the hillside.

They're outgunned and outmanned by the Russian invaders, 5km (3 miles) away in the eastern Donetsk region, who are inching closer.

Incoming American ammunition is expected to help, but how the Ukrainian government is addressing its need to recruit is controversial.

A new mobilisation bill passed earlier in April was criticised for not including a limit on time served. A clause aimed at demobilising soldiers after three years was dropped at the army's request.

Now, war-weary troops have told the BBC the military needs to "rethink" how it recruits.

Despite Kyiv lowering the conscription age to find replacements, it's not just a numbers game.

Thousands of trained troops like Oleksandr, a radio operator in the 21st separate Mechanised Brigade, have been fighting for the best part of two years without a proper rest.

"If we go home," he says, "inexperienced soldiers might be able to hold the line against the Russians, but a lot of them will die."

He taps his handset in a bunker where he also sleeps with four other soldiers. The thickness of the air tells you it's well lived in.

Outside, the woodland provides an illusion of calm, periodically jarred by a whistling artillery shell overhead.

This time last year, the arrival of spring's hard soil brought a sense of optimism with an anticipated counter-offensive. The conditions make it easier to move men and machinery.

Today, it just makes these troops' job of digging new defences more difficult.

"My men have become professionals after fighting for so long," says their commander with the call sign "Chyzh", proudly.

He points to their mobile rocket launcher under camouflage netting.

"They know each vehicle is like a woman," he claims. "Each one is individual, with her own whims and characteristics."

Tucked away, their 1970s truck symbolises the current state of Ukraine's military. Old-fashioned in many ways yet modern in others - with a GPS guiding system - it lacks one key resource: rockets.

While Russia's army isn't a model of modern warfare, it is advancing on multiple parts of the eastern front line. It's why we're seeing new Ukrainian trenches being dug 30km (19 miles) back.

The invading forces have learnt tactical lessons and enjoy air superiority. Moscow has also drastically increased weapons production and is mobilising men at a faster rate than Ukraine can.

The sentiment in our wooded trench mirrors the Ukrainian government's mantra of "fighting for as long as it takes".

While the soldiers we meet might not have felt they could speak entirely freely, it's not an issue for Illia, whom I meet in the relative privacy of the main square of Kramatorsk, in eastern Ukraine.

Illia, a combat medic, thinks the military has been dishonest about what signing up means.

He argues that it would be more effective if recruiters told new soldiers that the first six months are "super hard" - but that they would then be trained for more specific roles.

"The infantry is the hardest job in the military," he says.

Tired as Illia is, the idea of fighting alongside a petrified conscript in a trench is not an appealing one. He also thinks a lack of transparency about the realities of the battlefield is further putting men off from registering to fight.

"What if this war lasts 10 years?"

Back in Kyiv, as we stroll down her normal jogging route, local MP Inna Sovsun explains to me why she abstained on the mobilisation bill vote. Her partner serves as a frontline medic.

"I spend countless nights worrying where he is," she explains. "It's the experience of millions of Ukrainians."

Ms Sovsun thinks there should be more of a focus on rotation, arguing Ukraine has enough men of a fighting age to swap with the 500,000 or so who are currently fighting.

"There are highly trained soldiers who can't be swapped, but what about the people in trenches?" she asks. "It takes time to train them, but what if this war lasts for 10 years?"

"We can't pretend to rely on the same people who started serving on day one."

Until now, Ukraine's army recruitment has been hampered by historical corruption claims and diminishing volunteers.

Now ministers are pursuing two key objectives: restoring trust in the system whilst increasing the pressure on men to fight.

Both made more difficult by the battlefield not going Ukraine's way.

Additional reporting by Hanna Chornous, Thanyarat Doksone, Anastasiia Levchenko and Hanna Tsyba.