who rushed to the building on Kasr al-Nile street, near the iconic , tended to 14 people including passersby and transported five to hospitals, the source said.
An investigation has been launched to assess the cause of the sudden collapse of the heritage-listed building, Cairo's governorate said on its Facebook page.
It said the damaged four-storey property housed several stores and two residential apartments.
An AFP reporter at the scene surrounded by rubble, full of ambulances and fire trucks, said "the building is gutted and barely holding up".
Read also:
Building collapses in Egypt occur frequently due to lax enforcement of construction and maintenance regulations as well as developers illegally adding floors to boost profits.
In July, a building in the upmarket Cairo suburb of Zamalek, close to embassies, showed deep cracks prompting authorities to evacuate residents fearing its collapse.
One of the worst such urban disasters struck in 2014 when a Cairo building caved in, killing 19 people.
Downtown Cairo boasts buildings that are nearly 200 years old, blending Islamic and European motifs, neo-classical columns and ornate decorations.
Many UNESCO-listed have fallen into disrepair and ruin in Egypt's drive for urban renewal.
Follow us on , and to stay connected