Sunni fighters led by an al-Qaeda breakaway group expanded their offensive in a volatile western province, capturing three strategic towns and the first border crossing with Syria to fall on the Iraqi side.
It is the latest blow against prime minister Nouri Maliki, who is fighting for his political life even as forces beyond his control are pushing the country towards a sectarian showdown.
In a reflection of the bitter divide, thousands of heavily-armed Shiite militiamen – eager to take on the Sunni insurgents – marched through Iraqi cities in military-style parades on streets where many of them battled US forces five years ago.
The towns of Qaim, Rawah and Anah are the first territory seized in predominantly Sunni Anbar province, west of Baghdad, since fighters from the Islamic State of Iraq and the Levant group overran the city of Fallujah and parts of the provincial capital of Ramadi earlier this year.
The capture of Rawah on the Euphrates River and the nearby town of Anah appeared to be part of march towards a key dam in the city of Haditha, which was built in 1986 and has a hydraulic power station that produces some 1,000 megawatts. Destruction of the dam would adversely impact the country’s electrical grid and cause major flooding.
Iraqi military officials said more than 2,000 troops were quickly dispatched to the site of the dam to protect it against a possible attack by the Sunni militants.
Rawah’s mayor, Hussein Ali al-Aujail, said the militants ransacked the town’s government offices and forced local army and police forces to pull out. Rawah and Anah had remained under government control since nearby Fallujah fell to the Sunni militants in January.
The Islamic State’s Sunni militants have carved out a large fiefdom along the Iraqi-Syrian border and have long travelled back and forth with ease, but control over crossings like that one in Qaim allows them to more easily move weapons and heavy equipment to different battlefields.
Syrian rebels have already seized the facilities on the Syrian side of the border and several other posts in areas under their control.
Police and the army said the Sunni insurgents seized Qaim and its crossing, about 200 miles west of Baghdad, after killing about 30 Iraqi troops in day-long clashes on Friday. The officials said people were now crossing back and forth freely.
Chief military spokesman Lt Gen Qassim al-Moussawi acknowledged Qaim’s fall, saying troops aided by local tribesmen sought to clear the city of “terrorists”.
Mr Maliki’s Shiite-dominated government has struggled to push back against Islamic extremists and allied Sunni militants who have seized large swathes of the country’s north since taking control of the second-largest city of Mosul on June 10 as Iraqi government forces melted away.
The prime minister, who has led the country since 2006 and has not yet secured a third term after recent parliamentary elections, has also increasingly turned to Iranian-backed Shiite militias and Shiite volunteers to bolster his beleaguered security forces.
The parades in Baghdad and other mainly cities in the mainly Shiite south revealed the depth and diversity of the militia’s arsenal, from field artillery and missiles to multiple rocket launchers and heavy machine guns, adding a new layer to mounting evidence that Iraq is inching closer to a religious war between Sunnis and Shiites.
Mr Maliki has come under growing pressure to reach out to disaffected Kurds and Sunnis, with many blaming his failure to promote reconciliation led to the country’s worst crisis since the US military withdrew its forces nearly three years ago.
In Baghdad, about 20,000 militiamen loyal to anti-US Shiite cleric Muqtada al-Sadr, many in military fatigues and even some wearing red berets, white gloves and combat helmets, marched through the sprawling Shiite Sadr City district.
The area saw some of the worst fighting between Shiite militias and US soldiers before a ceasefire was reached in 2008 that helped stem the sectarian bloodshed that was pushing the country to the brink of civil war.
Similar parades took place in the southern cities of Amarah and Basra, both strongholds of al-Sadr supporters.
Grand Ayatollah Ali al-Sistani, the most respected voice for Iraq’s Shiite majority, joined calls for Mr Maliki to reach out to the Kurdish and Sunni minorities a day after US president Barack Obama challenged him to create a leadership representative of all Iraqis.
The cleric normally stays above the political fray and his comments, delivered through a representative, could ultimately seal Mr Maliki’s fate.
Mr Maliki’s State of Law bloc won the most seats in the April vote, but his hopes to retain his job have been thrown into doubt, with rivals challenging him from within the broader Shiite alliance. In order to govern, his bloc, which won 92 seats, must first form a majority coalition in the new 328-seat legislature, which must meet by June 30.
If Mr Maliki were to relinquish his post now, according to the constitution, the president, Jalal Talabani, a Kurd, would assume the job until a new prime minister is elected. But the ailing Mr Talabani has been in Germany for treatment since 2012, so his deputy, Khudeir al-Khuzaie, a Shiite, would step in for him.
Iraq enjoyed several years of relative calm before violence increased a year ago after Mr Maliki moved to crush a Sunni protest movement against what the minority sect claimed was discrimination and abuse at the hands of his government and security forces.
Meanwhile, four separate explosions killed 10 people, including two policemen, and wounded 22 in Baghdad yesterday. And in an incident harking back to the sectarian killings in 2006 and 2007, two bodies, presumably Sunnis, were found riddled with bullets in Baghdad’s Shiite district of Zafaraniyah.
Iraqi officials said the militants also seized Rutba, about 90 miles east of the Jordanian border, late Saturday. Residents were today negotiating with the militants to leave after an army unit on the town's outskirts threatened to start shelling.