There has been no let-up in violence in Afghanistan even though the Taliban and the United States appear close to a historic pact for U.S. troops to withdraw in exchange for a Taliban promise the country would not be used as a base from which to plot attacks by extremists.
The blast, in the west of the city during the morning rush hour, sent a huge cloud of grey smoke billowing into the sky.
The Taliban said a "recruitment center" had been attacked by one of their suicide bombers.
"A large number of soldiers and police were killed or wounded," the Taliban said in a statement.
The bomb went off when a vehicle was stopped at a checkpoint outside the police station, said interior ministry spokesman Nasrat Rahimi.
A health ministry spokesman said 95 wounded people had been taken to hospitals. Most of them were civilians, including women and children, he said.Separately, security forces conducted raids in several parts of Kabul overnight and destroyed a major militant hideout, the main security service said.