The attack took place in the provincial capital of Gardez city, 100km south of Kabul, reports Xinhua news agency.
The injured included 15 members of the training centre and the toll might increase, the police added.
No group has so far claimed responsibility for the attack.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
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Doraiah Chowdary Vundavally is a Software engineer at VTech . He is the news editor of SocialNews.XYZ and Freelance writer-contributes Telugu and English Columns on Films, Politics, and Gossips. He is the primary contributor for South Cinema Section of SocialNews.XYZ. His mission is to help to develop SocialNews.XYZ into a News website that has no bias or judgement towards any.