The blasts occurred around 1:30am at Huseni Dalan, an important 17th century center of learning for the Shia community.
The Shias were preparing for the trademark procession on the occasion of Ashura when the blasts took place, a police officer said.
The Ashura is observed on 10th day of Islamic month of Muharram to commemorate the martyrdom of Hazrat Imam Hussain, the grandson of Prophet Mohammad.
No group claimed responsibility for the attack.
Most of the victims were men, but some of them women, Daily Star quoted a police officer as saying.
One person was killed and 87 others injured in the blasts.
Fears of violence have been heightened this year after Taliban splinter groups pledged allegiance to the Syria- and Iraq-based Islamic State, which has repeatedly targeted Shias.
Locals and law enforcement agencies rushed the wounded to hospitals.
People were seen running frantically after the blasts.
"We think these blasts were carried out to create a chaotic situation in the country," he said.
