A Ukrainian tank heads away from the embattled eastern town of Avdiivka, Ukraine, on Feb. 3. (Brendan Hoffman/Getty Images)

From the center of this beleaguered eastern Ukrainian town, air bursts from exploding shells could be seen just a few hundred yards away Friday, and the sound of intense outgoing and incoming rounds echoed from several directions.

“This is the worst fighting we’ve seen in Ukraine since 2014 and early 2015,” said a visibly upset Alexander Hug, head of the Organization for Security and Cooperation in ­Europe’s monitoring mission in Ukraine, who was standing near a makeshift humanitarian aid station where shrapnel had collapsed a tent overnight. The town has been bombarded ­relentlessly every night this week in the latest flare-up of hostilities between Russian-backed separatists and Ukrainian forces.

According to Hug, both sides are making use of heavy weapons such as the multiple-launch Grad missile system, and they are doing so in plain sight of OSCE observers. Grads, along with 152mm and 122mm ­artillery, were banned under the Minsk II agreement, which was signed two years ago after the catastrophic battle of Debaltseve.

A woman speaks on her cellphone amid the ruins of a building after shelling in Donetsk, near Avdiivka in eastern Ukraine, on Feb. 3. Heavy shelling hit both government- and rebel-controlled areas of eastern Ukraine as fighting continued, and international monitors issued a sharp call for the sides to still their guns. (Alexander Ermochenko/Associated Press)

In the town of Avdiivka, whose prewar population of 35,000 has been reduced to an estimated 15,000 to 20,000, residents who have elected to stay voiced utter dismay Friday.

“I have to sleep in my bathroom. They’re going to kill me in my bathroom,” shouted 72-year-old Liliana Nikolaina, who had gathered with other women near another makeshift aid station, set up in a low-rise building next to a set of apartment blocks a few minutes’ walk from where Hug spoke. “I can’t believe it’s happening again.”

“This is the fourth year of war,” said Vera, 56, who declined to give her last name. “We’re all Ukrainians, we’re for a united Ukraine, and we just want this war to finally stop. Tell Poro­shenko to find a way to end this,” she said — referring to Ukrainian President Petro ­Poroshenko — before bursting into tears.

While the fighting has been largely kept to the outskirts of Avdiivka during the day, the nighttime has been hellish for residents. Shells have landed indiscriminately throughout the town, and civilian casualties are racking up. Some residents are still without power or heat lost during the fighting, and most are relying on humanitarian aid boxes for food, bedding, candles and other supplies.

Ukrainian servicemen give free food to Avdiivka residents at a humanitarian aid center Friday. (Evgeniy Maloletka/Associated Press)

A woman enters a tent to charge her phone at a humanitarian aid center in Avdiivka. (Evgeniy Maloletka/Associated Press)

Residents charge their phones at the aid center. (Evgeniy Maloletka/Associated Press)

Outside the aid station where the women were gathered Friday, a shell had fallen just hours earlier. A 25-year-old rescue worker was killed in the blast when ­shrapnel riddled the ambulance he was sitting in. Hours later, blood and matter were still visible in the front seat of the vehicle.

Authorities reported that a woman was also killed overnight Thursday, and the Ukrainian military said that three of its soldiers were killed, as well.

An apartment block on the edge of town was shelled, and the fourth-floor apartment of 70-year-old Anatoliy Nikolai­vich and his wife, Elena, took a direct hit from a 122mm shell.

“Everything is destroyed,” Nikolai­vich said as he stood amid the remnants of his home. “It was so beautiful, and now look at this, it’s all gone.”

He and his wife had been sleeping in their daughter’s first-floor apartment when the shell landed.

A view of a damaged building in Avdiivka on Friday. (Markiian Lyseiko/European Pressphoto Agency)

The woman reported killed in the overnight shelling was several hundred feet away in another mid-rise apartment building. The top-floor apartment was destroyed, and the blast ripped through the one below it, where British photographer Christopher Nunn was interviewing her. She died in the blast, and he suffered shrapnel wounds to his face and eyes.

Tetiana Gruba, an adviser to the Dnipropetrovsk regional government on war-related matters, said doctors in the city of ­Dnipro, where Nunn was evacuated, had saved his eyesight but were unsure how well he will be able to see.

A Ukrainian commander, Yevhen Deydey, 25, said he expects the escalation of hostilities to continue.

He said his troops had received text messages as part of a psychological warfare effort mounted by the separatists. Among them were messages that read: “They’ll find your body when the snow melts”; “You’re just meat to your commanders”; and “You’re like Germans at Stalingrad.”

Although residents in town say they’re hopeful that a cease-fire can be negotiated, they are bracing for the worst. Most are once again spending their nights in basements.

Ira Kosova writes a message to her daughter Maria, 17, on the window of a bus in Avdiivka evacuating several dozen people Friday to the town of Sviatohirsk, away from the fighting. (Brendan Hoffman/Getty Images)