The building was struck in Chasiv Yar, about 20 kilometres from Kramatorsk, expected to be a major target of Russian forces as they advance westwards in eastern Ukraine.
Russian rockets struck a residential area in the eastern Ukrainian town of Chasiv Yar, destroying a five-storey apartment block and killing at least 18 people.
According to the rescue services, more are still under the rubble, while five others have been rescued immediately after the attack on Sunday following the partial collapse of the building.
Rescuers deployed a crane to lift a concrete slab and used their hands to dig through the debris, while residents who survived the attack retrieved personal belongings and told stories of their escape.
"We ran to the basement, there were three hits, the first somewhere in the kitchen," said a resident who gave her name as Ludmila.
"The second, I do not even remember, there was lightning, we ran towards the second entrance and then straight into the basement. We sat there all night until this morning." Another survivor, who gave her name as Venera, said she had wanted to save her two kittens.
Pavlo Kyrylenko, the Donetsk region's governor, said the strike took place on Saturday evening in Chasiv Yar, a town of some 12,000 inhabitants. It lies about 20 kilometres southeast of Kramatorsk — a city that is expected to be a major target of Russian forces as they advance slowly westwards.
The Ukrainian emergency services initially gave a death toll of six, but later said it had risen to 10 before it reached 15 on Sunday night and the latest figure of 18 on Monday morning.
"I was in the bedroom, I came out and everything started shaking, collapsing. What saved me was the wave of the explosion that propelled me into the toilet, all bloody. I barely got out," said one resident, who did not want to give her name.
According to one of the heads of the rescue operation, Vyacheslav Boytsov, the rescue team initially managed to establish contact with some of the people who were alive under the rubble.
"There is a chance of finding them," he told AFP. "They have enough air, they can breathe. They tell us they are waiting to be rescued."
Russian forces used heavy Iskander missiles in the strike, Boytsov said, quoting a preliminary assessment by experts.
Russia raising 'true hell' in east
The Donetsk region is one of two provinces along with Luhansk that make up the Donbas region, where separatist rebels have fought Ukrainian forces since 2014. Last week, Russia captured the city of Lysychansk, the last major stronghold of Ukrainian resistance in Luhansk.
On Saturday, Ukraine's Luhansk governor Serhiy Haidai said Russian forces were managing to “raise true hell” in the eastern industrial heartland.
Haidai said Russia launched over 20 artillery, mortar and rocket strikes in the province the previous night and its forces were pressing toward the border with the Donetsk region.
After the seizure of Lysychansk, some analysts predicted Moscow’s troops likely would take some time to rearm and regroup.
But Haidai said that so far there had been "no operational pause announced by the enemy", which was "still attacking and shelling our lands with the same intensity as before".
Later he added that the Russian bombardment of Luhansk was suspended because Ukrainian forces had destroyed ammunition depots and barracks used by Moscow troops.
Ukrainian authorities said that in addition to the Donbas, the Russian army continued to bomb the northeastern Kharkiv region over the weekend, where it opened fire with artillery, multiple rocket launchers and tanks.
Governor of the Kharkiv region Oleh Synehubov described the bombardment that killed three and wounded at least 28 by Sunday as “absolute terrorism”.
Syneihubov said on Telegram that the Russian forces only hit civilian targets in three missile strikes on the northeastern city.
One of the missiles destroyed a school, another a residential building while the third landed near warehouse facilities, said Syneihubov.
According to officials, the attacks are expected to continue as Moscow is preparing "new actions" after four and a half months of the war, despite the Kremlin's earlier claims of putting its offensive on pause.