By Zainullah Stanekzai

LASHKAR GAH, Afghanistan (Reuters) - Afghanistan's Taliban have released drone footage showing a suicide bomber driving a Humvee into a police base in Helmand province and blowing it up this month.

An Afghan government official said the video posted online appeared to be authentic.

The use of video taken by a drone is unusual for the Taliban but more common among the more media-savvy Islamist groups fighting in Iraq and Syria.

The video, 23 minutes long, begins with the purported suicide bomber speaking in front of the Humvee, a vehicle provided to Afghan forces by American advisers.

"This is the happiest moment of my life," the man says, dressed in a black turban and white tunic.

"I am telling the Afghan stooge forces to repent and join the Taliban or we will use this equipment the foreigners gave them, against them and they can't do anything about it."

Later, a drone-mounted camera silently films the Humvee speeding towards a compound.

Facing no apparent resistance, the Humvee barrels into the middle of the base, detonating in flames in front of a large building and producing a cloud of smoke and dust, obscuring the entire compound.

A government official in Helmand said the district police chief and several other officials were killed in the attack on October 3, when Taliban militants overran much of Nawa district.

The official, who declined to be named, said the video depicting the attack appeared to be authentic.

The video's producers used graphics of target-like overlays to give the footage a video game-like feel, an effect used by Islamic State in Syria and Iraq.

U.S.-led forces have often used military-grade drones against the Taliban in Afghanistan's long war since 2001. Commercial drones favored by hobbyists and video producers are far simpler and cheaper.

In, June the Afghan government banned media from using camera drones near sensitive government sites on security grounds.

(Writing by Josh Smith; editing by Andrew Roche)