Iraqi forces say they have launched an offensive to clear the desert bordering Syria of so-called Islamic State (IS).
Army, police and paramilitary units are advancing into areas of Salahuddin, Nineveh and Anbar provinces that form part of a region known as al-Jazira.
The operation comes days after Iraqi forces recaptured Rawa, the last Iraqi town controlled by the jihadist group.
Prime Minister Haider al-Abadi has said he will announce “the final defeat” of IS once it is routed in the desert.
Many IS militants are believed to have fled to sparsely-populated parts of the al-Jazira region after suffering a series of defeats across Iraq and Syria.
The desert was used as a sanctuary by a precursor to IS, which was weakened by a US troop surge and the creation of Sahwa (Awakening) councils by Sunni Arab tribesmen who rejected its brutality.
The desert, Rawa and a number of other towns both side of the Iraqi-Syrian border were designated by IS as part of its “Euphrates Province”.
The region was of strategic importance to IS as the group used routes through it to transfer fighters, weapons and goods.
It was also symbol of the group’s intention to eradicate borders and lay to rest the 1916 Sykes-Picot agreement, which is resented by many Arabs and Kurds.
IS has been driven out of about 95% of the land the group once held in Iraq and more than 4.4 million Iraqis are no longer living under its rule, according to the US-led coalition supporting the Iraqi government.