ERBIL, Iraq — Iraq’s fracturing deepened Thursday as Kurdish forces poured into the strategic northern oil city of Kirkuk after government troops fled, while emboldened Sunni militants who seized two other important northern cities this week moved closer to Baghdad and issued threats about advancing into the heavily Shiite south and destroying the shrines there, the holiest in Shiism.
The rapidly unfolding developments came as Prime Minister Nouri al-Maliki’s entreaties for emergency powers stalled because of inaction by parliament, which seemed paralyzed.
The inability or unwillingness of al-Maliki’s armed forces to hold their ground only compounded the crisis.
The U.S. government’s apparent rejection of al-Maliki’s requests for airstrikes on the Sunni militants reflected a deep reluctance by the Obama administration to re-entangle the U.S. militarily in Iraq.
But President Barack Obama, offering his first detailed comments on the Iraq crisis, told reporters at the White House on Thursday that his national security advisers were examining “all options” on how to stop the Sunni militant advances.
There were unconfirmed reports that Iran, an ally of al-Maliki’s Shiite-led government, had sent Revolutionary Guards into Iraq to help him fight the Sunni militants.
Kurdish officials said Thursday that their forces had taken full control of Kirkuk in northern Iraq, a city dear to many Kurds, as government troops abandoned their posts there.
Militants aligned with the jihadist Islamic State of Iraq and the Levant swept across the porous border from Syria on Tuesday to overrun Mosul, Iraq’s second-largest city.
They have been driving toward the capital since then, capturing the town of Tikrit, the birthplace of Saddam Hussein, seizing parts of the oil refinery city of Baiji and threatening Samarra, a city sacred to Shiites just 70 miles north of Baghdad.
With its oil riches, Kirkuk has long been at the center of a political and economic dispute between Kurds and successive Arab governments in Baghdad.
The disappearance of the Iraqi army from the city Thursday appeared to leave Kirkuk’s fate in the Kurds’ hands.
The urgency was underscored Thursday when an insurgent spokesman, Abu Mohammed al-Adnani, exhorted the militants to advance on the Iraqi capital..
After overrunning Mosul and Tikrit, the insurgents poured down the main north-south highway to reach Samarra.
On the way, the insurgents were said to have taken positions in parts of the important refining town of Baiji, north of Tikrit, but there were conflicting accounts Thursday as to who was in control there and whether the refinery was operating.