Several people have been killed in a bombing in the centre of the Afghan capital Kabul, President Ashraf Ghani has said.
Interior ministry spokesman Sediq Sediqqi said a suicide attacker had detonated a vehicle.
Dozens are reported injured. Gunfire can still be heard in the area.
A Taliban spokesman said the group was responsible a week after it said it was launching its "spring offensive". It had warned of "large-scale attacks".
Tuesday's bombing happened in a residential neighbourhood close to the ministry of defence and military compounds, during the morning rush hour.
"The first blast was carried out by a suicide bomber in a car and possibly one or two bombers are still resisting," Mr Sediqqi was quoted as saying.
"The scene of the attack has been completely cordoned off by Afghan security forces."
A health ministry spokesperson told the BBC more than 40 injured people had been taken to Kabul hospitals.
The presidential palace condemned the attack "in the strongest possible terms".
The Taliban has over the past year enjoyed a resurgence, buoyed by the withdrawal of most Nato and US forces at the end of 2014, and a flood of foreign fighters joining their ranks.
It now controls sizeable parts of Afghanistan.