At least three including a security guard were killed and 12 others were wounded in the incident, said Zmaray Sahak, the spokesman of Zabul Security Command.
The injured who were in critical conditions were transferred to Kandahar province.
No group has so far claimed responsibility for the attack.
Since 2001 when the United States invaded Afghanistan, over 100,000 people have been killed in the war, including more than 4,000 ISAF soldiers and civilian contractors, more than 62,000 Afghan national security forces, 31,000 civilians and even more Taliban members.