BAGHDAD (AP) -- The al-Qaida-inspired group that captured two key Sunni-dominated cities in Iraq this week vowed on Thursday to march on to Baghdad, raising fears about the Shiite-led government's ability to slow the assault following the insurgents' lightning gains.
Fighters from the militant group known as the Islamic State of Iraq and the Levant took Saddam Hussein's hometown of Tikrit on Wednesday as soldiers and security forces abandoned their posts and yielded ground once controlled by U.S. troops.
That seizure followed the capture of much of Mosul, Iraq's second-largest city, the previous day. The group and its allies among local tribesmen also hold the city of Fallujah and other pockets of the Sunni-dominated Anbar province to the west of Baghdad.
Baghdad does 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.
The capital, with its large Shiite population, would be a far harder target for the militants. So far, Islamic State fighters have stuck to the Sunni heartland and former Sunni insurgent strongholds where people are already alienated by the Shiite-led 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 if they tried to advance on the capital.
In contrast, online video posted Thursday showed some Tikrit residents celebrating the militant takeover. As Islamic State fighters drove through largely empty streets in a captured military Humvee and a pickup truck mounted with an anti-aircraft gun, what appeared to be a few dozen people shouted "God is great," and celebratory gunfire could be heard. The video appeared authentic and was consistent with AP reporting.
The Islamic State's spokesman vowed to take the fight into the capital at the heart of Shiite Prime Minister Nouri al-Maliki's government. In a sign of the group's confidence, he even boasted that its fighters will take the southern Shiite cities of Karbala and Najaf, which hold two of the holiest shrines for Shiite Muslims.
"We will march toward Baghdad because we have an account to settle there," he said in an audio recording posted on militant websites commonly used by the group. The statement could not be independently verified.
Meanwhile, 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 over Kurdish claims on territory outside their enclave.
Kurdish security forces known as peshmerga took over an air base and other posts abandoned by the Iraqi military in the ethnically mixed flashpoint city of Kirkuk, Brig. Halogard Hikmat, a senior peshmerga official told the Associated Press. But he denied reports the whole city was under peshmerga control.
"We decided to move ... because we do not want these places with the weapons inside them to fall into the hands of the insurgents," said Hikmat. Iraqi government officials could not be reached to confirm the account.
A force of 20 pick-up trucks carrying Islamic State militants attacked peshmerga positions near the town of Sinjar, on a highway between Mosul and the Syrian border. The two sides battled for four hours late Wednesday night in a firefight that killed nine militants and wounded four peshmerga, Hikmat said.
Militants also attacked an Iraqi security checkpoint Thursday in the town of Tarmiyah, 50 kilometers (31 miles) north of Baghdad, killing five troops and wounding nine, said officials, speaking on condition of anonymity because they were not authorized to talk to the media.
