There was no immediate claim of responsibility for the blast, which went off in the men's reception area of a west Kabul wedding hall.
A Kabul emergency hospital said 20 wounded people had been brought in.
'Unfortunately, the blast caused civilian casualties,' Interior Ministry spokesman Nasrat Rahimi said.
He put the number of wounded in the tens and said details were being gathered. Interior Ministry spokesman Nusrat Rahimi tells media the explosion happened at around 10:40 pm. local time.
Witnesses said members of the minority Shi'ite Muslim community were holding the wedding reception.
Sunni Muslim militants including the Taliban and ISIS have repeatedly attacked the Shi'ite Hazara minorities in Afghanistan and neighbouring Pakistan over the years.
Sources and eyewitnesses said the hall was packed with guests when the explosion happened. Kabul's brightly lit wedding halls can hold hundreds of people.
The Shahr-e-Dubai wedding hall is located in police district 6 (PD6) which covers areas like Darul Aman in the west of Kabul.
Footage on social media shows women screaming outside the wedding hall, while they are shocked by the explosion.
Sources said the casualties might be high.
The explosion shattered more than a week of calm in the Afghan capital. Ten days ago a Taliban car bomb aimed at Afghan security forces ripped through a busy west Kabul neighborhood, killing 14 people and wounding 145 — most of them women, children and other civilians.
About 20,000 foreign troops, most of them American, are in Afghanistan as part of a US-led NATO mission to train, assist and advise Afghan forces.
Some US forces carry out counter-terrorism operations.
Three weeks ago, a Taliban suicide bomber killed 14 people and wounded 145, also in western Kabul, in an attack that the government said raised questions about the militants' commitment to peace despite expectations of a deal with the US.
The US and Taliban insurgents have reported progress in talks on an agreement centred on a US troop withdrawal from Afghanistan in exchange for a security guarantee from the Taliban.
Sunday 18 August 2019 00:19