The US seeks to reassure despite an unwavering desire to withdraw its military
By Jim Muir
BBC News, Baghdad
The sudden upsurge of violence in Iraq has set the alarm bells ringing and raised many disturbing questions. Does it mean the situation is sliding back out of control, as US troops prepare to leave Iraqi cities by the end of June and quit Iraq as a whole by 2011?
Four deadly suicide bombings in the space of two days brought back dark memories of the not so distant days in 2006 and 2007 when such attacks were taking place almost daily.
On Thursday, a suicide bomber - some witnesses said it was a woman - detonated explosives among a crowd of displaced people being given food relief by Iraqi police. More than 30 died, including 10 policemen.
Around the same time, another bomber walked into a roadside restaurant in near Baquba in Diyala province on the pilgrim route from the Iranian border north-east of Baghdad and blew himself up.
More than 50 people were killed, the vast majority of them Iranian pilgrims going to or from Shia shrines in Iraq. It was the most deadly single attack so far this year.
On Friday, the most venerated Shia site in Baghdad, at Kadhemiya, was the target for a double suicide bombing which rapidly replaced the Diyala attack as the year's worst, with more than 60 worshippers and pilgrims killed.
Violence is predicted to rise as US troop numbers start to be reduced
It was the kind of blatant provocation that triggered and fuelled the horrendous spiral of brutal violence between Sunnis and Shiites that took thousands of lives in 2006 and 2007.
Many died in massive, indiscriminate bomb attacks on crowded markets and holy places, actions blamed on Sunni militants from the insurgency.
The Shia militias struck back, abducting, torturing and killing thousands of Sunnis, whose bodies were found by the dozens daily, dumped randomly around Baghdad and elsewhere.
With around 150 people killed in just two days this week, Iraqis are wondering whether the latest attacks herald a return to those black times.
Nobody can be sure that they don't.
But so far, they are a blip on the screen - a big blip, but not one that takes the country anywhere near back to the levels of violence prevailing two years ago.
And despite a number of other deadly incidents earlier this month - particularly a rash of six car bomb explosions across Baghdad which killed around 30 people on 6 April - the recent bombings do not yet add up to the kind of sustained trend that would signal a fundamental reversal of the situation.
With April nearly over, roughly 250 people are believed to have died so far this month from acts of violence, including the latest attacks.
That is still at a level below 10% of that prevailing during the worst months of 2006-7, when the number of people known to have died sometimes went beyond 3,000 in a single month.
During those two years, the average number of Iraqis killed every single month was 2,170 according to the website Iraq Body Count (www.iraqbodycount.org) which has assiduously tracked Iraqi civilian casualties since 2003.
Those figures are minimal and incomplete, and the monthly average also includes a period towards the end of 2007 when the security improvement had already begun.
So the latest attacks and deaths, terrible though they may be, come nowhere close to the levels of violence which raged throughout those two traumatic years.
Nor have provocations such as the attack on the Kadhemiya shrine and others directed against Shiite pilgrims yet provoked the kind of sectarian backlash and reprisals that characterised 2006-7.
But the dangers are there, and the latest escalation has clearly stirred concern among both the Americans and the Iraqi authorities.
Prime Minister Nouri Maliki ordered an immediate investigation into how the Kadhemiya bombings could have happened despite strict security measures supposedly in place at the shrine.
The officers in charge of security there have also been suspended from duty pending the investigation.
The US plans to pull combat troops out of Iraq in the next two years
US military commanders believed they had broken the back of the bomb networks supplying explosives into the Baghdad area.
But three big suicide attacks in the capital in the space of two days, following the spate of car bombings on 6th April, has exposed gaps that the insurgents - presumed to be Sunni militants linked to al-Qaeda or in the same line - have been swift to exploit.
Even before the attacks of the past two days, Prime Minster Nouri Maliki had already expressed anxiety over the situation.
In 2007, he declared that the insurgency and al-Qaeda had been defeated, and that 2008 would be the year of economic development for Iraq.
But last Sunday, he warned that the danger from "terrorist cells" was still there.
"We have succeeded in re-establishing security, but maintaining it is more difficult," he said.
Even before the latest attacks, the senior American commander in Iraq, Gen. Ray Odierno, suggested that US troops might stay on beyond the end of June in Mosul and Baquba - two cities which have not yet been brought under control - if the Iraqi authorities requested.
The Iraqi government has not yet responded officially to the idea. But it is a formula that could end up being applied to Baghdad too if deadly attacks continue to be mounted there.
During her visit to Iraq on Saturday, US Secretary of State Hillary Clinton said that the US troop drawdown would be carried out "responsibly and carefully", and that Washington would ensure that the Iraqis had the tools they needed to ensure they had a secure country.
But she made it clear that the US remained committed to having its troops out of the country altogether in the next two years.
In other words, the strategic goal remains the same, but withdrawal tactics might be flexible to ensure no dangerous vacuums were left and that Iraqi forces were up to the task.
Mrs Clinton and other American officials have also stressed the need to integrate Iraq's Sunni community fully into political life and the security forces. This reflected fears that Sunni exclusion could favour a revival of the insurgency, which was always Sunni-based.
Iraqi leaders have also been slow to finalise nation-building legislation, particularly the oil and gas law, which is seen as crucial to holding the country together.
Lack of national political cohesion at the centre could undermine the unity of the Iraqi security forces if a situation of sectarian strain arises as the US troops withdraw.