Up to 40 people were feared killed and over 200 were injured Tuesday in a bombing in central Kabul apparently targeting Afghan security personnel, officials and news reports said.
"At least 15 NDS personnel have been killed," said an official of the National Directorate of Security, speaking anonymously.
Afghan media reported death tolls ranging from 24 to 40, in the first bombing in the capital to be claimed by the Taliban since the militants launched their spring offensive.
The car bomb appeared to target the 10th directorate, a compound that houses the VIP protection unit of the NDS, which provides security for high-ranking Afghan officials.
Ambulances took the injured to hospitals around the city, said Ismail Kawusi, a spokesman for the Health Ministry.
Following the bombing in a crowded area in the heart of Kabul, a number of attackers exchanged fire with security forces.
"An Afghan police CRU [Crisis Response Unit] is operating in the area and if any terrorist is still alive, our forces will send them to hell soon," Interior Minister spokesman Sediq Sediqi said.
President Ashraf Ghani condemned the attack, which he said "clearly shows the enemy's defeat in face-to-face battle" with the national security forces.
Taliban militants took responsibility for the attack.
"Following the first blast, a number of mujahideen entered the directorate, heavy fighting ongoing, heavy casualties to the slave enemy," spokesman Zabihullah Mujahid said on Twitter.
The attack was the deadliest in the capital since a truck bomb in August killed 15 and wounded more than 200 people.
The Taliban announced the start of their spring offensive last week before launching coordinated attacks in several provinces.