Fresh clashes have been reported around Tikrit as Iraqi government forces pressed ahead with an offensive to retake the northern city from Sunni insurgents.
AFP news agency quoted an army officer as saying on June 30 that troops controlled parts of the outskirts of the city, while witnesses reported air strikes overnight.
Fighters of the Islamic State in Iraq and the Levant (ISIL) captured Tikrit earlier this month as they swept across large parts of northern and western Iraq.
The Al-Qaeda splinter group declared a "caliphate," or Islamist state, in territories seized across Iraq and Syria.
An Iraqi Army spokesman, Qassim Atta, told Reuters news agency that the move sends a message both "to the region and the world" that ISIL has become "a threat to all countries."