Tikrit, the capital of the Salaheddin governorate and located less than 100 miles (160 kilometers) north of the capital, Baghdad, was attacked by unidentified insurgents who took control of some districts of the city, security officials told journalists.
An eyewitness told the BBC that insurgents entered the town from four different directions, and that at midday intense fighting was taking place in the city center, around the headquarters of the Salaheddin provincial government.
The identity of the attackers has yet to be confirmed, but members of ISIS—an Al-Qaeda splinter group—have already began pushing south from Mosul, seizing the town of Baiji, which contains Iraq’s largest oil refinery, on Tuesday.
The response of the Iraqi security forces in Iraq’s northern province of Nineveh has so far been ineffectual, with some units fleeing ahead of ISIS fighters, abandoning weapons, vehicles and even their uniforms, according to reports.
According to the International Organization for Migration, the fall of Mosul, Iraq’s second-largest city, has caused around 500,000 of its population of almost 2 million to flee, mostly northwards towards the autonomous region of Kurdistan.
Some remaining Mosul residents told reporters that ISIS fighters have urged municipal workers to return to work, a possible indication that it intends to occupy and hold the city over the long-term.
Analysts say that the organization’s latest offensive may be part of an attempt to unify the territory under its control in Iraq and neighboring Syria, where it has been battling the Syrian government and other rebel groups for control of the country’s eastern and northern provinces.
The group’s long-term goal is to create an “Islamic Emirate” in the territory of Iraq and Syria governed by its hard-line, radical interpretation of Islamic law.
So far, it has exploited political instability and sectarian divisions in Iraq and the war in Syria to seize territory from government forces and rebels alike.
The governor of Nineveh province, Atheel Al-Nujaifi, was also forced to flee north to Erbil, the capital of the Kurdish Regional Government (KRG). Speaking on Wednesday, he said that plans were being made to re-take Mosul with the help of local militias.
Iraq’s foreign minister, Hoshar Zebari, said that ISIS posed a “serious, mortal threat” to Iraq, and said Peshmerga militia from the KRG could assist government forces in attempts to recapture the city.
Speaking at an EU–Arab League conference in Athens on Wednesday, Zebari said: “We can push back on the terrorists . . . and there would be a closer cooperation between Baghdad and the [KRG] to work together and try to flush out these foreign fighters or elements who have disturbed the safety, the well-being of the population.”
Kurdish Peshmerga units are reported to have moved into position in Nineveh to block further ISIS advances, but are not currently planning offensive action.
The spokesman for the KRG’s Peshmerga Ministry, Brig. Gen. Halgord Hekmat, told London’s Guardian newspaper that “the sudden collapse of the Iraqi army has left us with no option but to fill some areas with our forces because we can’t have a security vacuum on our border.”
He added that Kurdish forces were awaiting an agreement between Erbil and Baghdad before joining the fighting.
Iraqi Prime Minister Nuri Al-Maliki called on Iraqis to stand firm on Wednesday, saying: “Do not give in. We are with you, the state is with you, the army is with you. Even if the battle is a long one, we will not let you down.”
He also said that he would “reorganize the armed forces to cleanse Nineveh of the terrorists and those who helped them.”