Two were killed and 18 wounded at the event, according to Afghan officials, the first big attack on the capital since a troop withdrawal agreement was signed last week in Doha between the United States and the Afghan Taliban.
The Taliban said in a statement they were not involved in the attack.
“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 gathering 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 Taliban.
Abdullah, runner-up in the last three Afghan presidential elections, each of which he disputed, has served as chief executive of a coalition government since 2014 and is also a former foreign minister.
Broadcaster Tolo News showed live footage of people running for cover as gunfire was heard.
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 that declared Ghani the winner of September’s presidential election.
Several people were killed in a similar attack on the same commemoration last year. The militant Islamic State group claimed responsibility for that attack.
Hazaras are mostly Shia Muslims. Minority Shias have been repeatedly attacked by militant groups in Afghanistan.
The US 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.
