Multiple explosions on March 21 killed at least six people and wounded 23 near a Shi'ite shrine in Kabul, a spokesman for the Afghan Health Ministry said.
Two children were among the wounded in the blasts, Kabul's Emergency Services director Muhammad Asim said.
There were conflicting reports about the cause of the blasts near the Karti Sakhi Shi'ite shrine and cemetery in a western Kabul neighborhood that is heavily populated by Shi'a Muslims.
Interior Ministry spokesman Nasrat Rahimi said an initial investigation indicated that three explosive devices had been remotely detonated, setting off the successive blasts as people gathered there to mark the holiday of Norouz, the pre-Islamic Persian New Year.
But Afghanistan's Defense Ministry said on Twitter that three rockets had been fired at civilian homes and Norouz gatherings -- adding that security forces arrested the attackers and secured the area.
All routes to the Shi'ite shrine were cordoned off by security forces, a local live TV broadcast showed.
Traditionally, people hoist green flags at the shrine and honor the dead at the cemetery by placing food beside graves.
There was no immediate claim of responsibility for the attack. The Taliban issued a statement denying responsibility.
An affiliate of the Islamic State (IS) extremist group has targeted Afghan Shi'a in the past. The extremist group considers Shi'a Muslims to be heretics.