Frontline Ukrainian troops face shortages of artillery shells and have scaled back some military operations because of a shortfall of foreign assistance, Brigadier General Oleksandr Tarnavskyy told Reuters.
"There's a problem with ammunition, especially post-Soviet (shells) - that's 122 mm, 152 mm. And today these problems exist across the entire front line," he said in an interview.
Tarnavskyy said the shortage of artillery shells was a "very big problem" and the drop in foreign military aid was having an impact on the battlefield.
"The volumes that we have today are not sufficient for us today, given our needs. So, we're redistributing it. We're replanning tasks that we had set for ourselves and making them smaller because we need to provide for them," he said, without providing details.
Weary Ukrainian troops on the southeastern front have gone on the defensive in some areas but are trying to attack in others, he said.
"In some areas, we moved (to defence), and in some we continue our offensive actions - by manoeuvre, fire and by moving forward. And we are preparing our reserves for our further large-scale actions," he said.
Russia is on the offensive in the east and trying to encircle the strategic eastern town of Avdiyivka, whose defence Tarnavskyy oversees.
"Their (Russian forces') intention remains (the same). The only thing is that their actions change, tactics change... attacks are carried out constantly," he said.
The situation in Avdiyivka was changing "every day and every night" with Russian forces regularly altering their tactics, having achieved "partial success in some areas at a depth of about 1.5 to 2km", he said.
"I believe that we are firmly maintaining these lines today," he said. "Today, the enemy is pressuring us with their numbers. They have never cared and will not care for their personnel."
Ukraine increasingly needs the means to defend itself against growing strikes by Russian attack drones, but Ukraine is banking on Western F-16 fighter jets being delivered, he said.
"With the presence of the F-16, it will be totally (different). In my opinion, as an infantry officer, the F-16 is like a Mercedes compared with a Zaporozhets (an old Soviet car)," he said. "Everyone is hoping."