The explosion reportedly took place in near a convoy of the coalition security forces in Maiwand district on Thursday afternoon.
Provincial governor spokesman Javid Faisal confirming the report said the incident took place around 1 pm local time in Kashaki market.
Mr. Faisal further added that a suicide bomber targeted a convoy of the coalition security forces in the busy market.
He said preliminary reports suggest at least 7 civilians were injured following the blast, however there are fears that casualties toll could rise.
In the meantime, a local security official speaking on the condition of anonymity said that nearly 30 civilians were killed or injured in the attack.
The source further added that four coalition security forces were also injured in the attack.