According to the local government officials, the incident took place near the provincial police commandment after a suicide bomber detonated his explosives.
Provincial governor’s spokesman Omar Zwak confirmed the incident and said at least five people were killed and more than forty others were wounded in the attack.
He said at least two security personnel and three civilians were among those killed.
No group including the Taliban insurgents has so far claimed responsibility behind the incident.
Helmand is among the volatile provinces in southern Afghanistan where the Taliban insurgents are actively operating in its various districts.
The group has launched numerous deadly attacks in some of the key districts of the province during the recent months.
The Taliban insurgents launched a coordinated attack by detonating Humvee vehicles and storming the security posts in Greshk district last month.
However, the attack was repulsed by the Afghan security forces after almost 48 hours of heavy gun battle that left several insurgents dead.