Security forces began the attack this morning and have succeeded in retaking government facilities in the city's south.
"Iraqi forces began a military operation to liberate the city of Tikrit and our forces were able to control the southern part of the city," Ahmed Abdullah Juburi, the governor of Salaheddin province of which Tikrit is the capital, told AFP.
An army colonel said the police academy and a hospital had been retaken, and Juburi confirmed those facilities were in government hands, along with the governorate headquarters.
Militants seized Tikrit on June 11 as part of a sweeping jihadist-led offensive that has overrun large areas of five provinces since it began last month.
Security forces folded under the weight of the initial onslaught, in some cases shedding uniforms and abandoning vehicles to flee.
They have since performed better, but have still struggled to regain ground from militants in offensive operations.
