At least 15 Taliban militants were killed in security operations in Helmand province over the past four days, local police said on Sunday.The operations, which have been launched in Baba Ji, Malgir, Loimanda, Shawal, Sistani and Nahr-e-Saraj areas, would last until lasting peace returns to the region, Xinhua news agency quoted police as saying.However, the police did not say if there were casualties among the security personnel.Taliban militants, who are active in parts of Helmand province and have challenged the government over the past couple of years, were yet to make comment.