The Ukrainian soldiers fighting on the frontline by day and battling Russian disinformation by night

In their underground bunker Ukrainian soldiers use their phones to fight a hybrid war, ITV News Security Editor Rohit Kachroo reports

During the day, they fight with guns, but at night in their underground bunker two hours from Mariupol, a group of Ukrainian soldiers use their phones to fight a hybrid war.

Dima, a 21-year-old soldier from Dnipro, tells me how for a little while before they go to sleep, they resume their attempt to “re-educate Russian people”, one by one through a campaign of cold calls. “Every evening we call in Russia random people and speak with them, it’s very funny,” he says.

“We try to speak without being aggressive, we try to speak about war and the political situation.” “We try to tell them that we are not Nazis, we are simple people like Russians, just some better,” he adds, smiling.

“Usually, they disagree with us but sometimes we meet normal people who support Ukraine.”

We are at an abandoned building which has become a makeshift military base in a village which was recently retaken by Ukrainian forces. Russian troops are two miles away​.

Dima spends the day waiting for whatever happens next, alongside other recruits who have become confidants, not just comrades.

Against the sound of occasional laughter and occasional outgoing fire, they prepare their weapons and keep up to date with the war on their smartphones.

Every now and again they sound triumphant - they have named their WiFi network ‘PutinH**lo’ (d***head) after a swear word slogan which has become a rallying cry for many Ukrainians.

But they are frustrated that they are struggling to break the stalemate which has set in alongside a sense of occasional boredom. Friendships forged on the battlefield have faced challenges, often in parallel with the pace of military progress.

The men talk of their “other lives”. For example, Dima worked as a model and a barista - his free time was dominated by the music of the Red Hot Chili Peppers and caring for his seven-year-old brother.

On the night of the invasion, February 24, he wrote to the youngster from close to the frontline, preparing him for the possibility that he might not return home. “I told him he must be a man, he must be (humane), he must love our mother and respect women. I told him he must be strong,” he says.

Dima still sends updates holding back details to prevent panic. He cannot wait to see his brother again - but says he has found many brothers since the war began.

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