Commander: War can spread to more of the country if Russia's tech grows.

If Russia keeps increasing weapons production and improving its technology with its allies' help, the war could expand beyond the east and south of the country, Lieutenant General Serhii Naiev, responsible for Ukraine's northern border defense, told ABC News.     "We are getting ready for that," he said. "We're building defenses, putting mines, and training our forces." In the first few months of the full-scale invasion, Russia attacked Ukraine from the east, north, and south.

Many regions, towns, and cities got firsthand experience of combat. But after Russia's quick strike failed, forcing it to withdraw troops from the north, most fighting became concentrated along the front line in the east and south, namely in Kharkiv, Luhansk, Donetsk, Zaporizhzhia, and Kherson oblasts. Other regions have experienced direct attacks due to Russia's waves of missile and drone strikes.

Naiev, who is also the commander of the Joint Forces, said that the importance of technology level outweighs how many munitions each side has.     The officer's observations were made during the ABC's visit to a training base for Ukraine's mobile air defense units, whose job it is to detect and intercept Russian drones in a way that's effective, flexible, and cheap. Mobile fire groups conduct reconnaissance and engage airborne targets, boasting a key advantage over stationary air defense systems with rapid deployment, as fast as 10 minutes, and the flexibility to maneuver across varied terrain.

These units destroyed 40% of Russia's recent mass strike by 75 drones on Nov.

25, according to the Air Force.

Russia launches record number of drones against Ukraine on Holodomor Memorial Day

Russia launched a record number of drones into Ukraine over the course of six hours on Holodomor Memorial Day on Nov.

25.

According to the Kyiv City Military Administration, "this was the largest drone attack since the beginning of the full-scale invasion."