The al-Qaeda inspired group that led the charge in capturing two key Sunni-dominated cities in Iraq this week vowed 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 on Wednesday took Saddam Hussein's hometown of Tikrit, as soldiers and security forces abandoned their posts and yielded ground once controlled by US forces.
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.
A spokesman for the Islamic State said the group has old scores to settle with Iraqi Prime Minister Nouri al-Maliki's government in Baghdad. The Iraqi leader, a Shiite, is trying to hold onto power after indecisive elections in April.
Al-Maliki has called on parliament to declare a state of emergency that would give him the "necessary powers" to run the country - something legal experts said could include powers to impose curfews, restrict public movements and censor the media. Lawmakers are expected to consider that request later today.
The ISIL spokesman, Abu Mohammed al-Adnani, also threatened that the group's fighters will take the southern Iraqi Shiite cities of Karbala and Najaf, which hold two of the holiest shrines for Shiite Muslims.
"March toward Baghdad because there was have an account to settle," he urged followers in a recording posted on militant websites commonly used by the group. The statement could not be independently verified.
Al-Adnani also said in the recording that one of ISIL's top military commanders, Adnan Ismail Najm, better known as Abu Abdul-Rahman al-Bilawi al-Anbari, was killed in the recent battles in Iraq.
Al-Adnani said Najm worked closely with the former leader of al-Qaeda in Iraq, Jordanian-born Abu Musab al-Zarqawi, who was killed by U.S. troops in 2006. Najm was later detained and spent years in prison before he was set free two years ago and prepared and commanded the operations that led to the latest incursions by the group in northern and central Iraq.
The Islamic State aims to create an Islamic emirate spanning both sides of the Iraq-Syria border. It has been able to push deep into parts of the Iraqi Sunni heartland once controlled by US forces because police and military forces melted away after relatively brief clashes.
The White House said Wednesday that the United States was "deeply concerned" about ISIL's continued aggression.
There were no reliable estimates of casualties or the number of insurgents involved, though several hundred gunmen were involved in the Tikrit fight, 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.
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.
So far, ISIL 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.
Mosul, the capital of Ninevah province, and the neighboring Sunni-dominated province of Anbar share a long and porous border with Syria, where the Islamic State is also active.
Mosul's fall was a heavy defeat for al-Maliki. His Shiite-dominated political bloc came first in April 30 parliamentary elections -- the first since the US military withdrawal in 2011 -- but failed to gain a majority, forcing him to try to build a governing coalition.
In addition to being Saddam's hometown, Tikrit was a power base of his once-powerful Baath Party. The former dictator was captured by U.S. forces while hiding in a hole in the area and he is buried south of town in a tomb draped with the Saddam-era Iraqi flag.
Meanwhile, a Kurdish military spokesman said Thursday that Kurdish forces are in full control of Iraq's oil-rich city of Kirkuk after the federal army abandoned its bases there.
Kirkuk lies at the heart of a long-running dispute between the federal government in Baghdad and the Kurds, who run their own autonomous region in the north of the country and have an armed force called the peshmerga.
"The whole of Kirkuk has fallen into the hands of peshmerga," said Jabbar Yawar, referring to the Kurdish forces. "No Iraqi army remains in Kirkuk now".
The move came after Iraqi soldiers fled their posts in the city of Mosul and several other towns and cities in the face of an onslaught by ISIL fighters.