In Sumy, a city located 560 kilometers from the Russian-Ukrainian border, there is a feeling that unrest will return again.

"After January 7, the attacks became more frequent. For the last 10 days, there have been such attacks almost every day," says Lt. Col. Roman Tkach.

The Ukrainian army says the Russians left "everything in the city". Just this past week, four buildings and 28 houses were hit by Russian missiles in the area in and around Sumy. And hotels, churches, gyms, restaurants and cafes are targets of artillery attacks.

As it says "The Guardian", a group of Russian saboteurs were caught last week trying to cross the border for unknown reasons. They fled as Ukrainian border police opened fire. Two weeks ago, an attack helicopter fired seven rockets at targets only 800 meters from this position.

"And rockets from the Grad system hit that hill there," said Artem Volinko, a 25-year-old senior lieutenant in the state border guard. "It's in the Ukrainian national park – maybe they wanted it to burn?"

There are many theories emerging within the Ukrainian military about this sudden and disturbing increase in activity in Sumy. Because probably much of the shelling seems to be completely random and chaotic. Drone attacks plague defense lines from dawn to dusk. But for now there are no large number of victims.

Oleksiy Danilov, chairman of Ukraine's National Security and Defense Council, which is coordinating the country's response to the invasion, said this week that Russia was preparing for "maximum escalation, gathering all possible forces" for a potential repeat of the February 24 attack from the north. south and east.

Artem Volinko was on the front lines when the Russians first launched their invasion. He ran a checkpoint with 10 other people in the village of Velika Pisarivka, not far from these trenches, and previously best known for being the place where 36 people were killed during the Nazi occupation in 1941.

"The Russians started attacking our checkpoint with less powerful weapons, but we couldn't see them in the dark, it was a chaotic attack," he recalled. "They also used a number of grenades."

The Ukrainians were then ordered to retreat to reserve positions, but Volinko was tasked with advancing again to an observation post to conduct reconnaissance while the defenders tried to control the size of the invasion.

"There was so much Russian military equipment that the smoke from their exhaust fumes obscured our view of the checkpoint. "Because of the big cloud of smoke, I couldn't even see our checkpoint," he said.

Tkach has another thinking: Sumy authorities are trying to convince the Ukrainian General Staff that they cannot afford to shift forces to Donetsk – and especially the city of Bakhmut – to facilitate Ukrainian efforts there.

Zelensky recently admitted that the situation there is "very difficult" with Russia claiming significant gains in recent days.

"The amount of military equipment we see now on the territory of Russia close to us does not pose a threat of a major invasion," Tkach said. "Perhaps they want as many Ukrainian military personnel as possible to remain in these positions and not be transferred to other hotspots."

That leaves Kyiv with a dilemma. Those troops fighting in Donetsk report that they are short on artillery, losing control of their defensive positions in the face of a Russian onslaught that looks set to destroy everything in front of them.