A powerful jihadist group inspired by al-Qaeda has opened a new battlefront with Iraqi security forces that could see it try to push into Baghdad, officials and analysts warn.
The latest clashes, just weeks before parliamentary elections, raise key questions over the capacity of the army and police to repel militant attacks. Anti-government fighters currently hold all of Fallujah, a town that is just a short drive from Baghdad, and other pockets of territory.
The push by the Islamic State of Iraq and the Levant (ISIL) into the Abu Ghraib area, sparking clashes in nearby Zoba and Zaidan and a failed assault on a military camp in Yusifiyah, illustrate the group's ambition, even with Fallujah under military siege.
In perhaps the most worrying sign of ISIL's capabilities, anti-government fighters paraded with dozens of vehicles last week in broad daylight in Abu Ghraib, just 20 kilometres from the capital, according to witnesses and videos posted to YouTube.
"ISIL fighters are trying to ease the pressure imposed on them in Fallujah," said an army lieutenant colonel, speaking on condition of anonymity.
"They have begun moving against weak villages between Baghdad and Fallujah, and to attack army units."
A police colonel, who also declined to be identified, added: "Members of ISIL have begun launching attacks on the army deployed in Abu Ghraib, and are threatening Baghdad."
In early January, militants overran Fallujah and parts of Ramadi, two towns in the western desert province of Anbar which shares a long border with Syria.
Government security forces have wrested back control of much of Ramadi.
A stalemate has persisted in Fallujah, with periodic clashes on the city's outskirts and regular shelling of what the army says are militant strongholds.
For around a week, soldiers have fought fierce battles in Zoba and Zaidan, which lie between the capital and Fallujah.
On Saturday, an explosion at a booby-trapped house in Garma, an area near the city of Fallujah, ensuing clashes with militants, and roadside bombings killed 21 soldiers.
"The objective appears to be to use this Anbar base as a launching pad for expansive operations towards the federal government in Baghdad," said Charles Lister, a visiting fellow at the Brookings Doha Centre.
Lister said the convoy in Abu Ghraib underlined the scale of ISIL's capacity to operate with near impunity in some areas.
"Iraqi security forces face some serious challenges to confronting [ISIL's] continued expansion in Iraq," he added.
Senior security officials say any move towards Baghdad by the jihadists is doomed to failure, and that attempts to open a new battlefront are a sign of weakness rather than strength.
"Entering Baghdad is impossible, this is not logical," said Brigadier General Saad Maan, spokesman for the interior ministry and the Iraqi capital's security command centre. "They do not have the power and we have huge military reinforcements to stop them.
"Our military has launched attacks against them on a daily basis in the Fallujah suburbs, and they have suffered lots of casualties," he added.
The bloodshed has pushed the violence to its worst since 2008, when Iraq emerged from a Sunni-Shiite sectarian war.
Zawahiri blasts infighting
Al-Qaeda chief Ayman al-Zawahiri has called for Islamist fighters in Syria to end the infighting that killed a one-time companion of Osama bin Laden this year, according to an audio tape posted online.
Zawahiri mourned the death of Abu Khaled al-Soury, who was killed by an al-Qaeda splinter group in a suicide attack in February, and lamented the "strife of the blind that has befallen the blessed land of the Levant". At the start of the year, the Islamic State of Iraq and the Levant (ISIL) began fighting rival rebels including other hardline Islamists. Some 4,000 people have been killed in the clashes, according to the Britain-based Syrian Observatory for Human Rights.
The fighting has hindered the battle against President Bashar al-Assad and pushed rival rebel groups to consolidate power in their respective areas of control. Al-Qaeda said it was breaking with ISIL in February after disputes over the group's refusal to limit itself to fighting in Iraq rather than in Syria, where the Nusra Front is al-Qaeda's affiliate.