Provincial administration spokesman Daud Ahmadi said on Tuesday that three bombers exploded their explosives in the security building in the Musa Qala district of the province, Press TV reported.
He said that the bombers also died during the attack.
The attack came hours after a bomb explosion hit a government office in western Herat province, killing at least 11 people, including three policemen.
The Taliban have claimed responsibility for the Herat attack.
Insecurity continues to climb across Afghanistan despite the presence of thousands of US-led forces in the Asian country.
The United Nations announced on February 4 that 2011 was the deadliest year on record for Afghan civilians. The death toll climbed by eight percent compared to the previous year and was roughly double the figure for 2007.
Source : Afghan Voice Agency (AVA), International Service