The building, "Rana Plaza", collapsed around 8:45 a.m. The building housed a market, several garment factories and a bank branch.
It developed cracks Tuesday and a day later, it collapsed. like a house of cards.
So far, nearly 100 people have been pulled alive out of the rubble.
Sohel Rana, a local who rescued several people by breaking open a window, told the Daily Star that cries for help wafted from under the rubble of the building.
The crash took place eight years after the collapse of Spectrum Garments in Baipail in Savar which left 64 workers dead.
Health Minister A.F.M. Ruhal Haque confirmed that 70 people were killed and over 600 injured in Savar Wednesday morning when the eight-storeyed building collapsed.
A few hundred more are believed to be trapped inside and rescuers fear the toll may rise significantly.
As many as 36 bodies were at Enam Medical College and Hospital in Savar.
Fire fighters and army personnel joined police and volunteers to rescue those trapped under the debris.
Families and relatives of the missing persons gathered in large numbers in front of the building. Fearing the worst, most of them were wailing.
President-elect Abdul Hamid, Prime Minister Sheikh Hasina and opposition leader Khaleda Zia in separate messages condoled the deaths.