At least eight people have been killed and about 400 injured by a powerful car bomb in the Afghan capital Kabul early on Friday morning, health officials have told the BBC.
Police say that the bomb went off in the Shah Shahid area of the city.
A security source told Reuters that the target was probably an army compound.
Injured people including children were rushed to hospital for treatment. Some bodies are feared buried in the wreckage of shops and businesses.
There has so far been no claim of responsibility for the explosion. However the Taliban will be the main suspects.
The BBC’s Khalil Noori says that most of the casualties are civilians.
Large truck bombs are unusual in the centre of Kabul are unusual, in part because police do not allow lorries to enter the city during daytime.
But smaller bombs and suicide attacks have become almost a weekly occurrence in the heavily fortified city.
On Thursday at least six people, including three policemen, were killed in a suicide bombing in eastern Afghanistan.
A lorry filled with explosives was detonated outside a police compound in Puli Alam, capital of Logar province.
The Taliban claimed the bombing, the first major attack since the militants confirmed last week that their leader, Mullah Omar, was dead.
On Monday the Afghan Taliban released a video which they said showed members of the group pledging allegiance to the new leader, Mullah Akhtar Mansour.