By Inna Varenytsia
NEAR VOVCHANSK, Ukraine (Reuters) - Ukrainian servicemen operating a howitzer in Kharkiv region near the Russian border work around the clock to stop an incursion by Moscow's troops, and they are finally getting the shells to do it.
Ukraine's defenders were hamstrung for months by shortages of artillery shells and other weapons as U.S. Congress held up billions of dollars worth of military aid. As the lawmakers in Washington argued, Russia's forces pressed their advantage on the frontlines, pushing forward on the eastern front.
With a $61 billion aid package belatedly approved by Congress last month, Ukraine's gunners say the crippling shortages are starting to ease.
Those in the northern districts of Kharkiv region say the fighting is more intense than their previous assignment in Bakhmut, the town in eastern Ukraine seized by Russia last year and reduced to rubble by months of fighting.
"It's 24/7, their infantry keeps coming, we keep fighting their attacks. At least we are trying to. Whenever possible, we take them down," said Pavlo, a gunner of Ukraine's 92nd Separate Assault brigade operating a howitzer.
"We were positioned in the Bakhmut area before, now we have been transferred here. It's much 'hotter' here. We didn't have shells there. Here, at least we have shells, they started delivering them. We have something to work with, to fight."
Russian forces pushed across the border earlier this month and say they have captured about a dozen villages.
The town of Vovchansk, 5 km (three miles) inside the border, remains the focal point of the incursion. Ukrainian forces control about 60 % of the town and are fighting house-to-house to fend off Russian attacks.
The stakes are high - capturing Vovchansk would be Russia's most significant gain since launching the assault. Kharkiv, Ukraine's second largest city, lies 70 km away.
"We see them walking down the road, 5 km away all the way from Shebekino," said Vitalii, commander of the brigade's artillery unit, referring to a town on the Russian side of the border.
"We see them walking on foot to their positions. As they move, we of course try to hit them , to inflict maximum casualties."
Officers pore over drone footage of Vovchansk, with smoke rising over different districts, to assess the situation below. Monitors are checked, calculations made.
Two men are tasked with ensuring the howitzer is well camouflaged - with tree boughs.
Vitalii is confident that the shells will keep coming as everyone is aware of the importance of holding their line.
"Yes, we will be getting ammunition because we are up against a large and serious enemy group," he said.
"If we can demonstrate now that we are able in such an extreme situation to stop the enemy's big scale assault on Kharkiv and Kharkiv region, the enemy will not dare to think of attacking Kyiv, Chernihiv, Sumy or Poltava region."