Nothing could be more cynically mendacious than the statement put out yesterday by Abu Musab al-Zarqawi, the Jordanian leader of al-Qaeda in Iraq, disclaiming responsibility for the suicide bomb that killed 24 Iraqi children on Wednesday. This act, unspeakable in its brutality, has caused such widespread revulsion among almost all Iraqis, Sunni and Shia, that it threatens to destroy any vestige of support for the outsiders who are maiming and killing Iraqis in their hundreds in the name of “national” liberation.

Al-Zarqawi claimed on a website that his insurgents fought only the “enemies of God”, defined as “the crusaders and their followers in the police and the army”, and were keen to avoid targeting civilians. Iraqis know better. Those recruited by, or associated with, his extremist group have not only deliberately targeted civilians, largely Shia, in an attempt to provoke sectarian bloodshed; they have deliberately chosen groups whose murders have caused the greatest horror: children, the old and pilgrims on Shia holy days.

Recent weeks have been among the bloodiest in Baghdad. At least nine soldiers were killed by an attack on an Iraqi army checkpoint on Monday. A day earlier, a suicide bomber killed more than 20 people queueing outside an army recruiting centre, the seventh time it had been attacked. More people were killed yesterday near the green zone by two suicide bombs. Despairing Iraqis are fleeing — to Jordan, to Europe, to anywhere where they can escape the bombings, sabotage and reprisals. The Shia-led Government of Ibrahim al-Jaafari has so far failed to put into place the “ring of concrete” it promised to erect around the centre of Baghdad. But the vast majority of Iraqis are still prepared to risk all in the quest to rebuild a country tortured through the decades. Nothing could demonstrate more strikingly this defiance than the queues of people who wait to sign up for police or government duties, despite the threats and the bombings.

It is time for all Iraqis to unite against the terrorist outsiders whose only agenda is to create chaos, in which they hope extremist views will thrive. This would mean that Sunnis finally accept the need to join the Shia majority in accepting positions of government responsibility. It would halt the bickering that has inhibited decisive government. And it would persuade all Iraqis, secular and religious, Shia, Sunni and Kurd, that unless they hang together, beyond them lies the abyss.

Much of the country is slowly improving, out of sight of the cameras. Trade is growing; power and water are returning despite the regular sabotage. But there are signs of a Shia backlash. Accusations that the police deliberately allowed suspects to suffocate in a metal container in sweltering heat have yet to be proved: negligence, vigilante actions or incompetence may well be to blame. But there is no doubt that police are resorting to the kind of routine torture against insurgents that may be understandable but can never be condoned. Shia restraint, remark-able up till now, is fraying, but the Shias have most to lose from chaos.

There must be no talk of pulling out British and American troops — again, that would play into the terrorists’ hands. And it is vital that neighbouring countries halt the flow of their own crazed citizens to Iraq. The outside threat is tangible and the outside responsibility is real.