Machine guns rattle from the rooftops as troops duck and weave below.
At an undisclosed location in East Anglia, the Ukrainian army's newest recruits are defending a mock village from attacking British infantry.
Members of the media were allowed to observe the exercise on condition they did not reveal its location for security reasons.
Mortars thud in the background as the defenders fire bursts of blank rounds like their lives depend on it.
Just days from now, they almost certainly will do. And by then the bullets will be for real.
For the fledgling soldiers will soon be on the front line of the fight to free their country after completing their basic training.
And their mentors from British regiments, along with elements of the Swedish, Finnish, Danish and Romanian armies, hope the skills they have learned will boost their chances of surviving to see victory.
READ MORE: Norfolk plea to find more homes for Ukrainians
READ MORE: £150m fund to support Ukrainian refugees
Alex, 33, was an administrator at a leisure resort before he volunteered for the army.
"In the beginning it was really hard because I had just come from civilian life," he said.
"I haven't been home for a long time, but in a couple of days we're going to go back and there's a war.
"I'm worried but I want to go back, I want to win the war obviously. I know we're going to win this war."
IT worker Stepan, 28, has swopped his keyboard for an assault rifle.
"It's good training, we've had a lot of scenarios," he said.
"It's a very good experience before we start fighting in real life. It won't be something we fear now, it's not going to give us stress."
Col James Thurstan commands Operation Interflex, the British-led multi-national initiative to train the Armed Forces of Ukraine.
"I'm always really impressed with the offensive spirit of the Ukrainians, their hope for the future and their willingness to fight for it," he said.
"The invasion by Putin was illegal and Britain is really clear it will support Ukraine and do everything it can."
Reservists from the Bury St Edmunds-based 3rd Batt Royal Anglian Regt have been among the trainers.
Second Lieut Luke Stannard, who hails from Ipswich and lectures at a Cambridgeshire college in Civvy Street, said: "The offensive spirit that they've shown is superb.
"The level of aggression is brilliant, their enthusiasm is unrivalled, they're highly motivated."
Pte Jessica Sacharczuk, a Norwich postal worker in her day job, added: "I'm quite amazed at how much effort they put in.
"If I was going to do this from the start, in the time they're given, I'm not sure I'd be able to get up to their standard."
After the guns fall silent, Ukrainians gather on a makeshift parade ground and stand to attention for Shche ne vmerla Ukraina, their national anthem: Ukraine has not yet perished.
"This is an intimate moment between soldiers," barks a British officer before the song begins.
Equipping Ukraine's volunteers with fighting skills and kit
More than 23,000 recruits from the Armed Forces of Ukraine have already received training in the UK since the start of 2022.
Each undergoes five weeks' training including trench and urban warfare, the law of armed conflict, battlefield first aid, counter drone measures and cyber warfare.
Hundreds of British soldiers along with personnel from Canada, New Zealand, Australia, Norway, Finland, Denmark, Sweden, Lithuania and the Netherlands have been mentoring Ukrainian recruits.
They aim to give volunteers with little to no military experience the skills to be effective in frontline combat including handling weapons, battlefield first aid, fieldcraft and patrol tactics.
The UK has also gifted clothing and equipment, giving each Ukrainian protective equipment including a helmet, body armour and first aid kit.
They will return home equipped with a field uniform and boots, cold and wet weather clothing, a rucksack, webbing, sleeping bag and entrenching tools.
In just days from now, they will be facing Russia's armed forces.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here