About 600 Iraqi National Guard and City Police engaged in their first major military operation called Operation Mutual Security. The operation was designed as a sweeping house-to-house search for weapons and terrorists in Mosul to be conducted by only Iraqi forces. Though approximately 150 U.S soldiers also helped by providing security in an outer cordon. The scope and aggresive nature of the operation had it dubbed by some as Operation Mosul Lock-Down. The operation netted some weapons and several terrorist suspects.