The Interior Ministry said a child was killed by the blast late Friday in the village of Torbagh along with the alleged suicide bomber and two other militants, Khaama Press reported. Kandahar in southern Afghanistan borders Pakistan.
Police seized a cache of explosives in the same district, officials said. They were allegedly destined for use in suicide attacks in Kandahar.
In Faryab province, a generally peaceful area in northern Afghanistan, police reported finding a vehicle loaded with explosives and weapons. The items seized included 23 artillery shells, two rockets, one BM-21 rocket, two barrels of explosives and two gas cylinders.
Officials believe militants planned to use the weapons and explosives to attack election teams in the run-up to April's presidential voting.