Buses carrying government workers have been targeted previously, but Danish said the bus was badly burned and it wasn’t immediately known whether the occupants were government employees.
“Right now all we know is that they were all civilians,” he told The Associated Press.
A spokesman for the interior ministry said the death toll was 24.
No one immediately took responsibility for the explosion but both the Taliban and the Islamic State group’s affiliate in Afghanistan have staged past attacks in Kabul.
Several prominent political leaders, such as Hazara leader Mohammad Mohaqiq, live in western Kabul. Several attacks have occurred in the neighbourhood, including the suicide attack last month that killed prominent Shiite Muslim cleric Ramazan Hussainzada, who was also a senior leader of the ethnic Hazara community.
Eyewitnesses to Monday’s attack said shattered glass from nearby buildings was scattered over the roadway.
“The sound was very strong. The ground shook,” said Mohammed Nader, who owns a convenience store in the neighbourhood.
The suicide attacker hit a minibus, said Nader.
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