Kabul, April 20 (IANS) Six armed militants were killed and 28 people were freed from a Taliban detention centre after the Afghan army launched a special operation in Helmand province, the Defence Ministry said on Tuesday."The commandos of Afghan National Army launched the raid in surrounding areas of Helmand's Musa Qala district. A gunfight took place when the troops arrived at the targeted facility, and six armed militants were killed," Xinhua news agency quoted the Ministry as saying in a statement.The freed people received medical checkups after they were shifted to an army camp, according to the statement.Taliban insurgents frequently detain civilians and off-duty soldiers from villages and highways and punish civilians for spying for government security forces.The Taliban militant group has not made a comment on the report so far. --IANS ksk/