An earthquake in south-eastern Turkey has killed more than 200 people, with hundreds more casualties feared. Rescue teams worked through Sunday night trying to free survivors crying out for help from under the rubble.

The Turkish interior minister, Idris Naim Sahin, said the 7.2 magnitude quake on Sunday killed 100 in the city of Van and 117 in the badly hit town of Ercis, 60 miles further north. The death toll was expected to rise.

Overseeing emergency operations in Ercis, Sahin said 1,090 people were known to have been injured and hundreds were missing.

Rescue efforts struggled to get into full swing following the quake, with electricity cut off as darkness fell on the towns and villages on the barren Anatolian steppe near the border with Iran.

Survivors and emergency service workers searched frantically through broken concrete using hands, shovels and torches or working under floodlights powered by mobile generators.

As dawn broke the scale of the devastation became clearer. At one crumpled four-storey building in Ercis a team of firemen from the largest south-eastern city of Diyarbakir were trying to reach four children believed trapped deep in an apartment block as concerned bystanders looked on.

Nearby, aid teams handed out parcels of bread and food, while people wrapped in blankets huddled around open fires after spending a cold night on the streets.

The prime minister, Recep Tayyip Erdogan, said there were an unknown number of people unaccounted for under the collapsed buildings of the stricken towns and he feared the worst for villagers living in outlying rural areas who had still to be reached.

“Because the buildings are made of adobe [mudbrick] they are more vulnerable to quakes. I must say that almost all buildings in such villages are destroyed,” Erdogan told a televised news conference in Van.

“We don’t know how many people are in the ruins of collapsed buildings, it would be wrong to give a number.”

There have been more than 100 aftershocks since the main quake, which lasted for about 25 seconds at 1.40pm local time on Sunday.

In Van, a bustling and ancient city on a lake ringed by snow-capped mountains and with a population of 1 million, cranes shifted rubble off a collapsed six-storey apartment block where bystanders said 70 people were trapped.

There was much more damage in Ercis with 55 buildings flattened, including a student dormitory, in a town of 100,000.

The Red Crescent said about 100 expert personnel had arrived at the earthquake zone to co-ordinate operations. Four thousand tents and 11,000 blankets, stoves and food were being distributed.

A tent city was being set up at the Ercis sports stadium. Access to the region was made more difficult as the earthquake caused the partial collapse of the main road between Van and Ercis, broadcaster CNN Turk reported.

The military said two battalions had been sent to assist the relief operations.

The Dogan news agency reported that 24 people were pulled from the rubble alive in the two hours after midnight.

One nurse told CNN Turk news channel the town’s hospital was so badly damaged that staff were treating the injured in the garden and bodies were being left outside the building.