Russian forces Tuesday began storming the steel mill containing the last pocket of resistance in Mariupol, Ukrainian defenders said, just as scores of civilians evacuated from the bombed-out plant reached relative safety and told of days and nights filled with dread and despair from constant shelling.

Osnat Lubrani, the U.N. humanitarian coordinator for Ukraine, said that thanks to the evacuation effort over the weekend, 101 people — including women, the elderly, and 17 children, the youngest 6 months old — were able to emerge from the bunkers under the Azovstal steelworks and “see the daylight after two months.”

One evacuee said she went to sleep at the plant every night afraid she wouldn’t wake up.

“You can’t imagine how scary it is when you sit in the shelter, in a wet and damp basement which is bouncing, shaking,” 54-year-old Elina Tsybulchenko said upon arriving in the Ukrainian-controlled city of Zaporizhzhia, about 140 miles (230 kilometers) northwest of Mariupol, in a convoy of buses and ambulances.

She added: “We were praying to God that missiles fly over our shelter because if it hit the shelter, all of us would be done.”

Evacuees, a few of whom were in tears, made their way from the buses into a tent offering some of the comforts long denied them during their weeks underground, including hot food, diapers, and connections to the outside world. Mothers fed small children. Some of the evacuees browsed racks of donated clothing, including new underwear.

The news for those left behind was grimmer. Ukrainian commanders said Russian forces backed by tanks began storming the sprawling plant, which includes a maze of tunnels and bunkers spread out over 11 square kilometers (4 square miles).

How many Ukrainian fighters were holed up inside was unclear, but the Russians put the number at about 2,000 in recent weeks, and 500 were reported to be wounded. A few hundred civilians also remained there, Ukrainian Deputy Prime Minister Iryna Vereshchuk said.

“We’ll do everything possible to repel the assault, but we’re calling for urgent measures to evacuate the civilians that remain inside the plant and to bring them out safely,” Sviatoslav Palamar, deputy commander of Ukraine’s Azov Regiment, said on the messaging app Telegram.

He added that throughout the night, the plant was hit with naval artillery fire and airstrikes. Two civilian women were killed and 10 civilians wounded, he said.

The U.N.’s Lubrani expressed hope for further evacuations but said none had been worked out.