Broadcaster Tolo News showed live footage of people running for cover as gunfire was heard
Gunmen attacked a ceremony in the Afghan capital Kabul on Friday where a top Afghan political leader, Abdullah Abdullah, was present but escaped unharmed.
Eighteen were wounded at the event, according to Afghan officials, the first substantive attack on the capital since a troop withdrawal agreement was signed in Doha between the United States and the Taliban Islamist militant group, who denied responsibility.
"The attack started with a boom, apparently a rocket landed in the area, Abdullah and some other politicians ... escaped the attack unhurt," Abdullah's spokesman, Fraidoon Kwazoon, who was also present, told Reuters by telephone.
The Taliban said in a statement they were not involved in the attack on the gathering, which marked the anniversary of the death of Abdul Ali Mazari, an ethnic Hazara leader who was killed in 1995 after being taken prisoner by the militants.
Broadcaster Tolo News showed live footage of people running for cover as gunfire was heard.
Afghan President Ashraf Ghani tweeted that the attack was "a crime against humanity and against the national unity of Afghanistan".
He added he had telephoned Abdullah, his longtime political rival. Abdullah is contesting an Electoral Commission announcement last month declaring Ghani the winner of September's presidential election.
Several people were killed in a similar attack on the same commemoration last year. Islamic State militants claimed responsibility for that attack.
Hazaras are mostly Shi'ite Muslims. Minority Shi'ites have been repeatedly attacked by Sunni Muslim militant groups in Afghanistan.
The United States has been trying to spearhead efforts towards a lasting peace arrangement. Violence decreased during a seven-day hold-down agreement with the Taliban leading up to last Saturday's deal, though the Taliban has since resumed attacks on Afghan forces.
A senior Western security official said all checkpoints in Kabul were on high alert.
"It's too early to say but for now we are intensifying security," the official said.