Al-Qaeda-inspired militants pushed deeper into Iraq's Sunni heartland, swiftly conquering Saddam Hussein's hometown of Tikrit as soldiers and security forces abandoned their posts and yielded ground once controlled by US forces.
The advance into former insurgent strongholds that had largely been calm before the Americans withdrew less than three years ago is spreading fear that Prime Minister Nouri al-Maliki, struggling to hold onto power after indecisive elections, will be unable to stop the Islamic militants as they press closer to Baghdad.
Fighters from the Islamic State of Iraq and the Levant militant group took control on Tuesday of much of Iraq's second-largest city, Mosul, sending an estimated half a million people fleeing from their homes. As in Tikrit, the Sunni militants were able to move in after police and military forces melted away after relatively brief clashes.
The group, which has seized wide swaths of territory, aims to create an Islamic emirate spanning both sides of the Iraq-Syria border.
The capture of Mosul - along with the fall of Tikrit and the militants' earlier seizure of the western city of Fallujah - have undone hard-fought gains against insurgents in the years following the 2003 invasion by US-led forces.
There were no reliable estimates of casualties or the number of insurgents involved, though several hundred gunmen were in Tikrit and more were fighting on the outskirts, said Mizhar Fleih, the deputy head of the municipal council of nearby Samarra.
An even larger number of militants likely would have been needed to secure Mosul, a much bigger city.
The militants gained entry to the Turkish consulate in Mosul and held captive 48 people, including diplomats, police, consulate employees and three children, according to an official in the office of Turkish Prime Minister Recep Tayyip Erdogan.
Turkish officials did not make any public comment on the seizure, but the state-run Anadolu Agency reported that Erdogan convened an emergency Cabinet meeting.
While the insurgents have advanced southward, Baghdad did not appear to be in imminent danger from a similar assault, although Sunni insurgents have stepped up car bombings and suicide attacks in the capital in recent months.
Iranian airlines cancelled all flights between Tehran and Baghdad due to security concerns, and the Islamic Republic has intensified security measures along its borders, Iran's official IRNA news agency reported.
The International Organization for Migration estimated 500,000 people fled the Mosul area.
