Iraqi and United States-led forces were last night preparing to launch a rescue mission for up to 150 Shia hostages held by Sunni insurgents.
The threat by Sunni militants in the town of Madaen, south of Baghdad, to execute the hostages unless Shias leave the area, intensified the growing sectarian fears.
The upsurge in violence across Iraq in the past four days has left claims made by the Pentagon that the tide is turning in Iraq and there are hopeful signs of a return to normality in tatters.
At least 17 Iraqis were killed during the day and two US soldiers were reported dead after a series of attacks.
Ironically, one reason why Washington can persuade the outside world that its venture in Iraq is finally coming right is that it is too dangerous for reporters to travel outside Baghdad or stray far from their hotels in the capital. The threat to all foreigners was underlined last week when an American contractor was snatched by kidnappers.
When I was travelling in the northern city of Mosul this week, my guards Kurdish members of the Iraqi National Guard said it was too dangerous for them to travel with me in uniform in official vehicles. They donned Arab gowns, hid their weapons and drove through the city in a civilian car.
Most violent incidents in Iraq go unreported. We saw one suicide bomb explosion, clouds of smoke and dust erupting into the air, and heard another in the space of an hour. Neither was mentioned in official reports. Last year US soldiers told the IoS that they do not tell their superiors about attacks on them unless they suffer casualties. This avoids bureaucratic hassle and "our generals want to hear about the number of attacks going down not up". This makes the official Pentagon claim that the number of insurgent attacks is down from 140 a day in January to 40 a day this month dubious.
US casualties have fallen to about one dead a day in March compared with four a day in January and five a day in November. But this is the result of a switch in American strategy rather than a sign of a collapse in the insurgency. US military spokesmen make plain that America's military priority has changed from offensive operations to training Iraqi troops and police. More than 2,000 US military advisers are working with Iraqi forces.
With US networks largely confined to their hotels in Baghdad by fear of kidnapping, it is possible to sell the American public the idea that no news is good news. General George Casey, the top US commander in Iraq, said recently that if all goes well "we shall make fairly substantial reductions in the size of our forces". Other senior US officers say this will be of the order of four brigades, from 17 to 13, or a fall in the number of US troops in Iraq from 142,000 to 105,000 by next year.
The real change leading to the US troop reduction is probably more in the US than in Iraq. The White House finds its military commitment in Iraq politically damaging at home. The easiest way to bring the troops home is, as in Vietnam, to declare a victory and full confidence in US-trained Iraqi forces to win the war. These soldiers and police supposedly number 152,000, but it is not clear who is being counted.
The figure may include the 14,000 blue-uniformed Iraqi police in Nineveh province, the capital of which is Mosul, with a population of 2.7 million. But Khasro Goran, the deputy governor and Kurdistan Democratic Party leader in Mosul, told the IoS that the police had helped insurgents assassinate the previous governor.
Mr Goran said that when guerrillas captured almost all of Mosul on 11 November last year, the police had collaborated, abandoning 30 police stations without a fight. "They didn't fire on terrorists because they were terrorists themselves," he said. Some $40m-worth of arms and equipment was captured by the insurgents. It is a measure of how far the reality of the war in Iraq now differs from the rosy picture presented by the media that the fall of Mosul to the insurgents went almost unreported abroad because most journalists were covering the assault by the US marines on Fallujah.
Despite the elections on 30 January, the US problem in Iraq remains unchanged. It has not been defeated by the Sunni Arab guerrillas but it has not defeated them either. The US army and Iraqi armed forces control islands of territory while much of Iraq is a dangerous no-man's land.
After overthrowing Saddam Hussein in 2003 the US tried direct rule, dissolving the Iraqi army and state. This provoked the Sunni rebellion. By early 2004 there was a danger that part of the Shia community would also rise up. Elections were promised. The victors at the polls in January were Shia parties, mostly militantly Islamic and often sympathetic to Iran. Donald Rumsfeld, the US Defence Secretary, visited Baghdad this week to stop Shia radicals taking over the Interior and Defence Ministries.
Iraq is now more sectarian. Sunnis boycotted the elections. The Kurds and Shias triumphed. The interim prime minister, Iyad Allawi, despite heavy US support, got only 14 per cent. If the Shia hostages taken on Friday are executed or Shias are forced to flee, then we are closer to a sectarian civil war.
The Sunni insurgency is not going to go away. US generals say there are only 12,000 to 20,000 guerrillas. But the real lesson of the past two years is that, though many of the groups in the resistance are fanatical or semi-criminal, they will still be sheltered by the Sunni community.
If the new Iraqi government succeeds in establishing itself it will be a largely Shia state with no more interest than the Sunnis in retaining a US presence. Iraqis say they sense that the US wants Iraq to be a weak state, and this they are bound to oppose.