The TV channel quoted a policeman in Kandahar as saying that "extremists were mining a car they were planning to use for an act of terror when a blast went off killing all the five on the spot."
Last year, suicide bombers conducted over 150 explosions in the country killing over a hundred civilians.
Earlier reports said 21 Taliban gunmen were captured in a military operation involving police and security officers in the central Afghan province of Vardak.
In Nangarhar, in the east of the country, Afghan police confiscated 1,030 kg of hashish and arrested three suspects in drug trafficking earlier in the day.
Afghanistan, where the Taliban regime was overthrown in the 2001 U.S.-led campaign, has seen a rise in violence in the last two years. The country is also the world's leader in opium trade, with almost all its arable lands being sown with poppy.