The gathering attended by senior Afghan figures, including Chief Executive Abdullah, came under gun and rocket attack on Friday, according to his spokesman.
“The attack started with a boom, apparently a rocket landed in the area, Abdullah and some other politicians … escaped the attack unhurt,” Fraidoon Kwazoon was quoted as saying by Reuters.
Interior ministry spokesman Nasrat Rahimi said women and children were among the dead with an additional 29 wounded.
Soon after the attack, police forces and police special forces units rushed to the scene. Rahimi said special forces units are carrying out clearance operations against the attackers.
President Ashraf Ghani condemned the attack, calling it “a crime against humanity.”
The Taliban denied responsibility for the attack.
Several people were killed in a similar attack, claimed by the Daesh terrorist group, on the same gathering held last year to commemorate the anniversary of the death of Shia Hazara leader Abdul Ali Mazari.
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The Friday attack came less than a week after the Taliban and the US signed a deal to end the two-decade war in Afghanistan.
The agreement, signed on Saturday in Qatar, sets out a timetable for the foreign forces to quit Afghanistan within 14 months.
On Wednesday, however, the United States carried out its first airstrike on Taliban fighters since the two sides signed the troop withdrawal agreement.
The incident in southern Helmand province came hours after President Donald Trump spoke by phone with chief Taliban negotiator Mullah Baradar Akhund on Tuesday, the first known conversation between a US leader and a top Taliban official.
The US invaded Afghanistan to overthrow a ruling Taliban regime in 2001. The Taliban now control or hold influence over more Afghan territory than at any point since then.
American forces have remained bogged down in the country ever since.
Trump has long expressed eagerness to bring American soldiers back home and to end the war as he seeks re-election in 2020.
About 2,400 US soldiers have been killed in the war. Over 100,000 Afghans have also been killed or injured since 2009, when the UN Assistance Mission in Afghanistan began documenting casualties.