Power was being restored across Bangladesh after the worst blackouts since 2014 cut supply to half the country, disrupting hospitals to road traffic and internet networks.
Four of Bangladesh's eight administrative divisions - home to about 96 million people, about 60 per cent of the country's population - lost electricity supply on Tuesday after a transmission line tripped, with some outrages persisting for as long as eight hours.
Supply was restored to much of Dhaka by about 9pm local time, and was being resumed across other regions, according to officials.
"Engineers and technicians are working tirelessly," the country's power division, which will form a committee to investigate the cause of the disruption, said in a statement. "The power supply will be completely normal soon."
Nasrul Hamid, state minister for power and energy, said earlier the blackouts had been triggered by "technical glitches" in the grid.
Traffic jammed unlit roads late on Tuesday and stores used candles and cellphone torches to serve customers.
As the outages dragged on for several hours, many apartment blocks in Dhaka were forced to switch off back-up generators that had been running on expensive diesel fuel.