In the now-abandoned industrial outskirts of Avdiivka, Ukraine, the 74th battalion of the Ukrainian army maintains several small positions within 325 feet of positions held by separatists troops of the Donetsk People's Republic (DNR). <br> <br> "Santa" gives the order to fire at separatist positions. The men are frustrated by their government's strict following of the ceasefire rules. They are often denied permission to fire into the grey zone and have to wait for the enemy to cross into their territory before firing. Christopher Occhicone

An unpaid volunteer unit attached to the 74th reconnaissance unit maintains one of the positions on the frontline. It is a tight-knit group that has fought together in nearly every major battle of the war and have yet to suffer a casualty. They use code names like "Santa" and "Donut" to protect their identities.<br> <br> "Pilot," an unpaid volunteer, poses for a portrait in the basement bunker while shelling continues outside. Christopher Occhicone

"Yar" looks at "Donut," who has recently arrived to join the volunteer unit on the frontline in Avdiivka. The volunteers spend the majority of the day in the bunker because of continuous shelling. Christopher Occhicone

"Santa" and "Donut" move between positions on the frontline in Avdiivka. The positions are several hundred feet from DNR positions and have been under near constant shelling for weeks, forcing the men to spend the majority of their time indoors. Christopher Occhicone

"Santa," an unpaid volunteer, poses for a portrait in the basement bunker while shelling continues outside. Christopher Occhicone

"Ivan" listens as shells land outside their position. Christopher Occhicone

"Shamon," an unpaid volunteer, poses for a portrait in the basement bunker while shelling continues outside. Christopher Occhicone

Men risk exposure to mortar attacks in order to call family. The only spot in the postion with cell service is located upstairs in a stairwell facing seperatist troops. Christopher Occhicone

A Ukrainian soldier operates a machine gun approximately 325 feet from separatist positions in Avdiivka, Ukraine. Because of sniper fire, it is the most dangerous position on the front. Christopher Occhicone

"Newt," an unpaid volunteer, poses for a portrait in the basement bunker while shelling continues outside. Christopher Occhicone

Father Sergiy arrived to visit troops in a bunker on the frontline in Avdiivka, Ukraine, under heavy enemy fire. He inspects a military intelligence officer's tattoo as they discuss the Orthodox Church's theory on killing the enemy during wartime. Christopher Occhicone

"Jar," an unpaid volunteer, poses for a portrait in the basement bunker while shelling continues outside. Christopher Occhicone

Despite the shelling continuing outside, Commander, "Newt," "Martin," "Pilot" and "Santa" watch a documentary about the battle for Donetsk airport, which they had participated in last year, in a bunker on the frontline in Avdiivka. Christopher Occhicone

Ceasefire monitors from the Organization for Security and Co-operation in Europe (OSCE) are shown shrapnel damage to a warehouse in Ukrainian-held territory outside Avdiivka. A Ukrainian soldier was killed outside of the warehouse as DNR troops have been randomly shelling the area to prevent the Ukrainian armed forces from fortifying their positions. Christopher Occhicone

"Martin," an unpaid volunteer, poses for a portrait in the basement bunker while shelling continues outside. Christopher Occhicone