BARACK Obama was under mounting pressure to send military help to Iraq last night as Iranian forces were reported to have joined Baghdad's government in its battle against an al-Qa'ida-inspired uprising.
Accused by Republicans of squandering the security gains won in Iraq by US forces, a defensive Mr Obama insisted he was looking at "all the options" to prevent the country unravelling.
But even as he spoke, Iran seemed poised to steal the initiative by sending troops to fight what its president, Hassan Rouhani, described as the "terrorist group that is acting savagely" in Iraq.
Reports emerged that two battalions of Iran's feared Revolutionary Guards were already operating in the country, where the government's own forces have so far shown little stomach for combat.
Iran's willingness to put troops on the frontline will give it a strategic advantage in Iraq over the US, which at most would likely offer airstrikes. Last night, the US State Department explicitly ruled out "boots on the ground".
The extraordinary developments of the past 72 hours raises the prospect of two bitter enemies – Iran and America – fighting the same foe, albeit for different goals.
Tehran's reported involvement in the crisis came as the militants pushed to within just over 50 miles of Baghdad, and declared a hardline form of Sharia law in the city of Mosul.
Leaflets distributed around the city instructed all citizens to pray at their local mosques five times daily, while smoking and drinking were outlawed and women ordered to dress modestly and stay indoors. The rules were issued in the name of the Islamic State of Iraq and al-Shams (ISIS), which said that any of its own fighters who breached them would have their hands amputated.
The leaflets were chillingly similar to ones first produced by al-Qa'ida when it seized swathes of western Iraq in 2004, and demonstrate how nearly a decade of nation building efforts by US and British forces are now at risk.
The sense of the high stakes at play led to bitter exchanges yesterday in Washington, where Republicans accused Mr Obama's administration of doing little to help Iraq's government, despite nearly a year of mounting al-Qa'ida activity.
Senator John McCain called for "drastic measures" to reverse the tide. Meanwhile, John Boehner, the House speaker, accused Mr Obama of "taking a nap" while militants marched on Baghdad.
Yesterday, the militants reached as far as the farming town of Dhuluiya, just over 50 miles from the Iraqi capital.
"We will march toward Baghdad because we have an account to settle there," said a message posted on an ISIS website.
With much of the Iraqi army having apparently deserted their posts, fears grew that Nouri al-Malik, the country's Shia prime minister, was likely to seek help from both his co-religionists in Iran and from Shia religious militias in Iraq. Such a move carries a high risk of plunging Iraq back into the Sunni-Shia civil war it suffered in 2006-7, when 30,000 people were killed.
Yesterday, there were reports that a general from Iran, Mr Maliki's main Shia ally and a sworn enemy of al-Qa'ida, was in Baghdad.
As the militants tightened the grip on the north of the country, Iraqi army troops had completely deserted the nearby city of Kirkuk, where Kurdish peshmerga forces – a well-trained ethnic militia loyal to the Kurdish government – were now in full control.
Requesting US help will be embarrassing for Mr Maliki, who gained political capital by pressurising America to pull its remaining troops from Iraq at the end of 2011. (© Daily Telegraph, London)