A general alert was issued for the rest of the city and for the international airport, officials said.
Jonjon Binay, a city councillor, said four people died immediately and four more died in hospital.
Blocks of cement had fallen from an upper storey of the shopping centre, hitting cars parked below and spreading a film of dust. Scores of windows in nearby shops were shattered.
A security guard said: “I was eating lunch when the ground shook. I thought it was an earthquake. Then the electricity went off.”
Manila has largely been spared a spate of bomb attacks by
Muslim separatists have been fighting in the southern Mindanao region, but few attacks have been carried out in the capital. A series of bomb blasts in 2000 killed at least 22 people.