Part of an apartment block in the Germasogeia area collapsed on Saturday, with people inside the building at the time, according to witness accounts.
The building was home to residents of African and Egyptian origin, while some of those inside managed to get out in time and others were away when the collapse happened, according to testimonies.
Witnesses said the block had a total of eight or nine flats, with at least four people living in each, raising concern over the exact number of residents who may have been in the building.
Residents in the area said they heard a loud noise, but at first thought it was explosions from Easter bonfires linked to the Resurrection celebrations.
The tenants themselves had said the apartment block had been deemed unfit, according to the same accounts.
Strong police, fire service and EMAK rescue teams remain at the scene and are continuing searches and operations in the rubble.
An operation to free a trapped person is underway by EMAK and Civil Defence, while three people were taken to the hospital by ambulance.
Rescue dogs are also assisting in the search operation.
(photos by Ioanna Mantzipa)