BAGHDAD: The Shiite-led government of Iraq's Prime Minister Nouri al-Maliki remained in paralysis Friday, unable to form a coherent response after al-Qaida-inspired militants blitzed and captured entire chunks of the nation's Sunni heartland this week, including major cities, towns, military and police bases as Iraqi forces melted away or fled.
The new reality is the biggest threat to Iraq's stability since the U.S. withdrawal at the end of 2011, and it has pushed the nation closer to a precipice that would partition it into Sunni, Shiite and Kurdish zones.
Fighters from the militant group known as the Islamic State of Iraq and Greater Syria (ISIS) Thursday vowed to march on Baghdad, joined by Saddam Hussein-era loyalists and other disaffected Sunnis.
Trumpeting their victory, the militants also declared they would impose Shariah law in Mosul, Iraq's second-largest city they captured on Tuesday, and other areas they seized.
In northern Iraq, Kurdish security forces moved to fill the power vacuum - taking over an air base and other posts abandoned by the military in the ethnically mixed city of Kirkuk.
Three planeloads of Americans were being evacuated from a major Iraqi air base in Sunni territory north of Baghdad, U.S. officials said, and Germany urged its citizens to immediately leave parts of Iraq, including Baghdad.
President Barack Obama said Iraq will need more help from the United States, but he did not specify what it would be willing to provide. Senior U.S. officials who spoke on condition of anonymity because they were not authorized to discuss the matter by name said Washington is considering whether to conduct drone missions in Iraq.
The U.N. Security Council met on the crisis, underscoring the growing international alarm over the stunning advances by the Islamic State.
Maliki had asked parliament to declare a state of emergency that would give him and his Shiite-led government increased powers to run the country, but the lawmakers failed to assemble a quorum Thursday.
Skirmishes continued in several areas Thursday. Two communities near Tikirt - the key oil refining center of Beiji and the city of Samarra, home to a prominent Shiite shrine - remained in government hands, according to Iraqi intelligence officials.
In Saddam's hometown of Tikrit, overrun by the militants on Wednesday, witnesses said fighters raised posters of the late dictator and Izzat Ibrahim al-Douri, his former deputy who escaped the 2003 U.S.-led invasion and has eluded security forces ever since.
Fighters loyal to his Naqshabandi Army as well as former members of Saddam's Baath Party were the main militant force in Tikrit on Thursday, said a resident who identified himself by his nickname, Abu Mohammed, out of concern for his safety. He said about 300 soldiers surrendered near the governor's office.
Lawmaker Hakim al-Zamili as well as two senior intelligence officials, who were not authorized to talk to the media, confirmed the involvement of Douri's group and other former Baathists and Saddam-era military commanders.
That could escalate the militants' campaign to establish an enclave into a wider Sunni uprising and lead to breaking up the country along ethnic and sectarian lines.
With its large Shiite population, Baghdad would be a far harder target for the militants. So far, they have stuck to the Sunni heartland and former Sunni insurgent strongholds where people are already alienated by Maliki's government over allegations of discrimination and mistreatment. The militants also would likely meet far stronger resistance, not only from government forces but by Shiite militias.
Shiite preacher Muqtada al-Sadr and the Asaib Ahl al-Haq Shiite militia vowed to defend Shiite holy sites, raising the specter of street clashes and sectarian killings.
Baghdad authorities tightened security and residents stocked up on essentials. Hundreds of young men crowded in front of the main army recruiting center in Baghdad on Thursday after authorities urged Iraqis to help battle the insurgents.
Security officials said the Islamic State fighters managed to take control of two weapons depots holding 400,000 items, including AK-47 rifles, rockets and rocket-propelled grenades, artillery shells and mortars. A quarter of the stockpiles were sent to Syria, they said.
The advances by the Sunni militants are a heavy defeat for Maliki. His Shiite-dominated political bloc came first in April parliamentary elections - the first since the U.S. military withdrawal in 2011 - but failed to gain a majority, forcing him to try to build a governing coalition.
"We do have a stake in making sure that these jihadists are not getting a permanent foothold in either Iraq or Syria, for that matter," Obama said in Washington.
Maliki and other Iraqi leaders have pleaded with the Obama administration for more than a year for additional help to combat the growing insurgency.
Separately, diplomatic efforts were underway to free 80 Turkish citizens held by militants in Mosul, an official in the Turkish prime minister's office said. The captives include 49 people seized in the Turkish consulate Wednesday, said an official, who spoke on condition of anonymity because of the sensitivity of the issue.
Kurdish fighters from the ethnic group's autonomous enclave in the north showed signs of taking a greater role in fighting back against the Islamic State. Their role is a potential point of friction because both Sunni and Shiite Arabs are wary of Kurdish claims on territory.
Kurdish security forces known as peshmerga took over an air base and other posts abandoned by Iraqi forces in Kirkuk, Brig. Halogard Hikmat, a senior peshmerga official told The Associated Press. He denied reports the whole city was under peshmerga control.