The assault in Shah Wali Kot district late Monday came just a day after 20 Afghan policemen were killed when Taliban fighters stormed their outposts in the neighboring province of Zabul, AFP reported.
No group has so far claimed responsibility for the Kandahar attack. But Taliban insurgents are intensifying their offensive and their strength is growing.
"Last night the enemies of Afghanistan attacked Achakzai camp of army corps 205 in Shah Wali Kot district," the defense ministry said in a statement.
Afghan forces have been engaged in fierce clashes with Taliban to contain insurgency in various parts of the country.
Taliban militants were removed from power following the 2001 US-led invasion of Afghanistan, but they have stepped up activities in recent months, attempting to overrun several provinces.
Thousands of foreign troops are still in Afghanistan, but apparently maintaining security remains an issue amid almost frequent incidents of violence across the country.